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\chap{Imaginary Journeys: The Lojban Space/Time Tense System}
\sect{Introductory}
This chapter attempts to document and explain the space/time
tense system of Lojban. It does not attempt to answer all
questions of the form ``How do I say such-and-such (an English
tense) in Lojban?'' Instead, it explores the Lojban tense
system from the inside, attempting to educate the reader into a
Lojbanic viewpoint. Once the overall system is understood and
the resources that it makes available are familiar, the reader
should have some hope of using appropriate tense constructs and
being correctly understood.
The system of Lojban tenses presented here may seem really
complex because of all the pieces and all the options; indeed,
this chapter is the longest one in this book. But tense is in
fact complex in every language. In your native language, the
subtleties of tense are intuitive. In foreign languages, you
are seldom taught the entire system until you have reached an
advanced level. Lojban tenses are extremely systematic and
productive, allowing you to express subtleties based on what
they mean rather than on how they act similarly to English
tenses. This chapter concentrates on presenting an intuitive
approach to the meaning of Lojban tense words and how they may
be creatively and productively combined.
What is \q{tense}? Historically, \q{tense} is the attribute
of verbs in English and related languages that expresses the
time of the action. In English, three tenses are traditionally
recognized, conventionally called the past, the present, and
the future. There are also a variety of compound tenses used in
English. However, there is no simple relationship between the
form of an English tense and the time actually expressed:
\begin{description}
\item[] I go to London tomorrow. I will go to London tomorrow. I am going to London tomorrow.
\end{description}
all mean the same thing, even though the first sentence uses
the present tense; the second, the future tense; and the third,
a compound tense usually called \q{present progressive}.
Likewise, a newspaper headline says \q{JONES DIES}, although it
is obvious that the time referred to must be in the past. Tense
is a mandatory category of English: every sentence must be
marked for tense, even if in a way contrary to logic, because
every main verb has a tense marker built into to it. By
contrast, Lojban brivla have no implicit or explicit tense
marker attached to them.
In Lojban, the concept of tense extends to every selbri, not
merely the verb-like ones. In addition, tense structures
provide information about location in space as well as in time.
All tense information is optional in Lojban: a sentence
like:
\begin{example}
mi klama le zarci\n
I go-to the market.
\end{example}
{\noindent}can be understood as:
\begin{description}
\item[] I went to the market. I am going to the market. I have gone to the market. I will go to the market. I continually go to the market.
\end{description}
as well as many other possibilities: context resolves which is
correct.
The placement of a tense construct within a Lojban bridi is
easy: right before the selbri. It goes immediately after the
\q{cu}, and can in fact always replace the \q{cu} (although in
very complex sentences the rules for eliding terminators may be
changed as a result). In the following examples, \q{pu} is the
tense marker for \q{past time}:
\begin{example}
mi cu pu klama le zarci\n
mi pu klama le zarci\n
I in-the-past go-to the market.\n
I went to the market.
\end{example}
It is also possible to put the tense somewhere else in the
bridi by adding \q{ku} after it. This \q{ku} is an elidable
terminator, but it's almost never possible to actually elide it
except at the end of the bridi:
\begin{example}
puku mi klama le zarci\n
In-the-past I go-to the market.\n
Earlier, I went to the market.
\end{example}
\begin{example}
mi klama puku le zarci\n
I go-to in-the-past the market.\n
I went earlier to the market.
\end{example}
\begin{example}
mi klama le zarci pu \optional{ku}\n
I go-to the market in-the-past.\n
I went to the market earlier.
\end{example}
\exref{10.1.2} through hyperref[ex:10:1:5]{1.5} are different only in emphasis. Abnormal
order, such as \exref{10.1.3} through hyperref[ex:10:1:5]{1.5} exhibit, adds emphasis to the words that
have been moved; in this case, the tense cmavo \q{pu}. Words at
either end of the sentence tend to be more noticeable.
\sect{Spatial tenses: FAhA and VA}
The following cmavo are discussed in this section:
vi VA short distance
va VA medium distance
vu VA long distance
zu'a FAhA left
ri'u FAhA right
ga'u FAhA up
ni'a FAhA down
ca'u FAhA front
ne'i FAhA within
be'a FAhA north of
(The complete list of FAhA cmavo can be found in \sectref{10.27}.)
Why is this section about spatial tenses rather than the
more familiar time tenses of \sectref{10.1}, asks
the reader? Because the model to be used in explaining both
will be easier to grasp for space than for time. The
explanation of time tenses will resume in \hyperref[sec:10:4]{Section
4}.
English doesn't have mandatory spatial tenses. Although
there are plenty of ways in English of showing where an event
happens, there is absolutely no need to do so. Considering this
fact may give the reader a feel for what the optional Lojban
time tenses are like. From the Lojban point of view, space and
time are interchangeable, although they are not treated
identically.
Lojban specifies the spatial tense of a bridi (the place at
which it occurs) by using words from selma'o FAhA and VA to
describe an imaginary journey from the speaker to the place
referred to. FAhA cmavo specify the direction taken in the
journey, whereas VA cmavo specify the distance gone. For
example:
\begin{example}
le nanmu va batci le gerku\n
The man \optional{medium distance} bites the dog.\n
Over there the man is biting the dog.
\end{example}
What is at a medium distance? The event referred to by the
bridi: the man biting the dog. What is this event at a medium
distance from? The speaker's location. We can understand the
\q{va} as saying: ``If you want to get from the speaker's
location to the location of the bridi, journey for a medium
distance (in some direction unspecified).'' This ``imaginary
journey'' can be used to understand not only \exref{10.2.1}, but also every other spatial
tense construct.
Suppose you specify a direction with a FAhA cmavo, rather
than a distance with a VA cmavo:
\begin{example}
le nanmu zu'a batci le gerku\n
The man \optional{left} bites the dog.
\end{example}
Here the imaginary journey is again from the speaker's
location to the location of the bridi, but it is now performed
by going to the left (in the speaker's reference frame) for an
unspecified distance. So a reasonable translation is:
\begin{description}
\item[] To my left, the man bites the dog.
\end{description}
The \q{my} does not have an explicit equivalent in the
Lojban, because the speaker's location is understood as the
starting point.
(Etymologically, by the way, \q{zu'a} is derived from
\q{zunle}, the gismu for \q{left}, whereas \q{vi}, \q{va}, and
\q{vu} are intended to be reminiscent of \q{ti}, \q{ta}, and
\q{tu}, the demonstrative pronouns \q{this-here},
\q{that-there}, and \q{that-yonder}.)
What about specifying both a direction and a distance? The
rule here is that the direction must come before the
distance:
\begin{example}
le nanmu zu'avi batci le gerku\n
The man \optional{left} [short distance] bites the dog.\n
Slightly to my left, the man bites the dog.
\end{example}
As explained in \sectref{10.1}, it would be
perfectly correct to use \q{ku} to move this tense to the
beginning or the end of the sentence to emphasize it:
\begin{example}
zu'aviku le nanmu cu batci le gerku\n
\optional{Left} [short distance] the man bites the dog.\n
Slightly to my left, the man bites the dog.
\end{example}
\sect{Compound spatial tenses}
Humph, says the reader: this talk of \q{imaginary journeys}
is all very well, but what's the point of it? --- \q{zu'a}
means \q{on the left} and \q{vi} means \q{nearby}, and there's
no more to be said. The imaginary-journey model becomes more
useful when so-called compound tenses are involved. A compound
tense is exactly like a simple tense, but has several FAhAs run
together:
\begin{example}
le nanmu ga'u zu'a batci le gerku\n
The man \optional{up} [left] bites the dog.
\end{example}
The proper interpretation of \exref{10.3.1} is
that the imaginary journey has two stages: first move from the
speaker's location upward, and then to the left. A translation
might read:
\begin{description}
\item[] Left of a place above me, the man bites the dog.
\end{description}
(Perhaps the speaker is at the bottom of a manhole, and the
dog-biting is going on at the edge of the street.)
In the English translation, the keywords \q{left} and
\q{above} occur in reverse order to the Lojban order. This
effect is typical of what happens when we \q{unfold} Lojban
compound tenses into their English equivalents, and shows why
it is not very useful to try to memorize a list of Lojban tense
constructs and their colloquial English equivalents.
The opposite order also makes sense:
\begin{example}
le nanmu zu'a ga'u batci le gerku\n
The man \optional{left} [up] bites the dog.\n
Above a place to the left of me, the man bites the dog.
\end{example}
In ordinary space, the result of going up and then to the left
is the same as that of going left and then up, but such a
simple relationship does not apply in all environments or to
all directions: going south, then east, then north may return
one to the starting point, if that point is the North Pole.
Each direction can have a distance following:
\begin{example}
le nanmu zu'avi ga'uvu\n
\T batci le gerku\n
The man \optional{left} [short distance] [up] [long distance]\n
\T bites the dog.\n
Far above a place slightly to the left of me,\n
\T the man bites the dog.
\end{example}
A distance can also come at the beginning of the tense
construct, without any specified direction. (\exref{10.2.1}, with VA alone, is really a
special case of this rule when no directions at all follow.)
\begin{example}
le nanmu vi zu'a batci le gerku\n
The man \optional{short distance} [left] bites the dog.\n
Left of a place near me, the man bites the dog.
\end{example}
Any number of directions may be used in a compound tense, with
or without specified distances for each:
\begin{example}
le nanmu ca'uvi ni'ava\n
\T ri'uvu ne'i\n
\T batci le gerku\n
The man \optional{front} [short] [down] [medium]\n
\T [right] [long] [within]\n
\T bites the dog.\n
Within a place a long distance to the right\n
\T of a place which is a medium distance downward\n
\T from a place a short distance in front of me,\n
\T the man bites the dog.
\end{example}
Whew! It's a good thing tense constructs are optional:
having to say all that could certainly be painful. Note,
however, how much shorter the Lojban version of \exref{10.3.5} is than the English version.
\sect{Temporal tenses: PU and ZI}
The following cmavo are discussed in this section:
pu PU past
ca PU present
ba PU future
zi ZI short time distance
za ZI medium time distance
zu ZI long time distance
Now that the reader understands spatial tenses, there are only
two main facts to understand about temporal tenses: they work
exactly like the spatial tenses, with selma'o PU and ZI
standing in for FAhA and VA; and when both spatial and temporal
tense cmavo are given in a single tense construct, the temporal
tense is expressed first. (If space were expressed before time,
then certain constructions would be ambiguous.)
\begin{example}
le nanmu pu batci le gerku\n
The man \optional{past} bites the dog.\n
The man bit the dog.
\end{example}
{\noindent}means that to reach the dog-biting, you must take an imaginary
journey through time, moving towards the past an unspecified
distance. (Of course, this journey is even more imaginary than
the ones talked about in the previous sections, since
time-travel is not an available option.)
Lojban recognizes three temporal directions: \q{pu} for the
past, \q{ca} for the present, and \q{ba} for the future.
(Etymologically, these derive from the corresponding gismu
\q{purci}, \q{cabna}, and \q{balvi}. See \hyperref[sec:10:23]{Section
23} for an explanation of the exact relationship between the
cmavo and the gismu.) There are many more spatial directions,
since there are FAhA cmavo for both absolute and relative
directions as well as \q{direction-like relationships} like
\q{surrounding}, \q{within}, \q{touching}, etc. (See \sectref{10.27} for a complete list.) But there are
really only two directions in time: forward and backward,
toward the future and toward the past. Why, then, are there
three cmavo of selma'o PU?
The reason is that tense is subjective: human beings
perceive space and time in a way that does not necessarily
agree with objective measurements. We have a sense of \q{now}
which includes part of the objective past and part of the
objective future, and so we naturally segment the time line
into three parts. The Lojban design recognizes this human
reality by providing a separate time-direction cmavo for the
\q{zero direction}, Similarly, there is a FAhA cmavo for the
zero space direction: \q{bu'u}, which means something like
\q{coinciding}.
(Technical note for readers conversant with relativity
theory: The Lojban time tenses reflect time as seen by the
speaker, who is assumed to be a \q{point-like observer} in the
relativistic sense: they do not say anything about physical
relationships of relativistic interval, still less about
implicit causality. The nature of tense is not only subjective
but also observer-based.)
Here are some examples of temporal tenses:
\begin{example}
le nanmu puzi batci le gerku\n
The man \optional{past} [short distance] bites the dog.\n
A short time ago, the man bit the dog.
\end{example}
\begin{example}
le nanmu pu pu batci le gerku\n
The man \optional{past} [past] bites the dog.\n
Earlier than an earlier time than now,\n
\T the man bit the dog.\n
The man had bitten the dog.\n
The man had been biting the dog.
\end{example}
\begin{example}
le nanmu ba puzi batci le gerku\n
The man \optional{future} [past] [short] bites the dog.\n
Shortly earlier than some time later than now,\n
\T the man will bite the dog.\n
Soon before then, the man will have bitten the dog.\n
The man will have just bitten the dog.\n
The man will just have been biting the dog.
\end{example}
What about the analogue of an initial VA without a direction?
Lojban does allow an initial ZI with or without following PUs:
\begin{example}
le nanmu zi pu batci le gerku\n
The man \optional{short} [past] bites the dog.\n
Before a short time from or before now,\n
\T the man bit or will bite the dog.
\end{example}
\begin{example}
le nanmu zu batci le gerku\n
The man \optional{long} bites the dog.\n
A long time from or before now,\n
\T the man will bite or bit the dog.
\end{example}
\exref{10.4.5} and \exref{10.4.6} are perfectly legitimate, but may not be very much
used: \q{zi} by itself signals an event that happens at a time
close to the present, but without saying whether it is in the
past or the future. A rough translation might be ``about now,
but not exactly now''.
Because we can move in any direction in space, we are
comfortable with the idea of events happening in an unspecified
space direction (\q{nearby} or \q{far away}), but we live only
from past to future, and the idea of an event which happens
\q{nearby in time} is a peculiar one. Lojban provides lots of
such possibilities that don't seem all that useful to
English-speakers, even though you can put them together
productively; this fact may be a limitation of English.
Finally, here are examples which combine temporal and
spatial tense:
\begin{example}
le nanmu puzu vu batci le gerku\n
The man \optional{past} [long time] [long space] bites the dog.\n
Long ago and far away, the man bit the dog.
\end{example}
Alternatively,
\begin{example}
le nanmu batci le gerku puzuvuku\n
The man bites the dog \optional{past} [long time] [long space].\n
The man bit the dog long ago and far away.
\end{example}
\sect{Interval sizes: VEhA and ZEhA}
The following cmavo are discussed in this section:
ve'i VEhA short space interval
ve'a VEhA medium space interval
ve'u VEhA long space interval
ze'i ZEhA short time interval
ze'a ZEhA medium time interval
ze'u ZEhA long time interval
So far, we have considered only events that are usually thought
of as happening at a particular point in space and time: a man
biting a dog at a specified place and time. But Lojbanic events
may be much more \q{spread out} than that: \q{mi vasxu} (I
breathe) is something which is true during the whole of my life
from birth to death, and over the entire part of the earth
where I spend my life. The cmavo of VEhA (for space) and ZEhA
(for time) can be added to any of the tense constructs we have
already studied to specify the size of the space or length of
the time over which the bridi is claimed to be true.
\begin{example}
le verba ve'i cadzu le bisli\n
The child \optional{small space interval} walks-on the ice.\n
In a small space, the child walks on the ice.\n
The child walks about a small area of the ice.
\end{example}
{\noindent}means that her walking was done in a small area. Like the
distances, the interval sizes are classified only roughly as
\q{small, medium, large}, and are relative to the context: a
small part of a room might be a large part of a table in that
room.
Here is an example using a time interval:
\begin{example}
le verba ze'a cadzu le bisli\n
The child \optional{medium time interval} walks-on the ice.\n
For a medium time, the child walks/walked/will walk\n
\T on the ice.
\end{example}
Note that with no time direction word, \exref{10.5.2} does not say when the walking happened: that would be
determined by context. It is possible to specify both
directions or distances and an interval, in which case the
interval always comes afterward:
\begin{example}
le verba pu ze'a\n
\T cadzu le bisli\n
The child \optional{past} [medium time interval]\n
\T walks-on the ice.\n
For a medium time, the child walked on the ice.\n
The child walked on the ice for a while.
\end{example}
In \exref{10.5.3}, the relationship of the
interval to the specified point in time or space is
indeterminate. Does the interval start at the point, end at the
point, or is it centered on the point? By adding an additional
direction cmavo after the interval, this question can be
conclusively answered:
\begin{example}
mi ca ze'ica cusku dei\n
I \optional{present} [short time interval -- present]\n
\T express this-utterance.\n
I am now saying this sentence.
\end{example}
{\noindent}means that for an interval starting a short time in the past
and extending to a short time in the future, I am expressing
the utterance which is \exref{10.5.4}. Of
course, \q{short} is relative, as always in tenses. Even a long
sentence takes up only a short part of a whole day; in a
geological context, the era of Homo sapiens would only be a
\q{ze'i} interval.
By contrast,
\begin{example}
mi ca ze'ipu\n
\T cusku dei\n
I \optional{present} [short time interval -- past]\n
\T express this-utterance.\n
I have just been saying this sentence.
\end{example}
{\noindent}means that for a short time interval extending from the past to
the present I have been expressing \exref{10.5.5}. Here the imaginary journey starts at the present, lays
down one end point of the interval, moves into the past, and
lays down the other endpoint. Another example:
\begin{example}
mi pu ze'aba citka le mi sanmi\n
I \optional{past} [medium time interval - future] eat my meal.\n
For a medium time afterward, I ate my meal.\n
I ate my meal for a while.
\end{example}
With \q{ca} instead of \q{ba}, \exref{10.5.6} becomes \exref{10.5.7},
\begin{example}
mi pu ze'aca citka le mi sanmi\n
I \optional{past} [medium time interval - present] eat my meal\n
For a medium time before and afterward, I ate my meal.\n
I ate my meal for a while.
\end{example}
{\noindent}because the interval would then be centered on the past moment
rather than oriented toward the future of that moment. The
colloquial English translations are the same --- English is not
well-suited to representing this distinction.
Here are some examples of the use of space intervals with
and without specified directions:
\begin{example}
ta ri'u ve'i finpe\n
that-there \optional{right} [short space interval] is-a-fish\n
That thing on my right is a fish.
\end{example}
In \exref{10.5.8}, there is no equivalent
in the colloquial English translation of the \q{small interval}
which the fish occupies. Neither the Lojban nor the English
expresses the orientation of the fish. Compare \exref{10.5.9}:
\begin{example}
ta ri'u ve'ica'u\n
\T finpe\n
that-there \optional{right} [short space interval - front]\n
\T is-a-fish\n
That thing on my right extending forwards is a fish.
\end{example}
Here the space interval occupied by the fish extends from a
point on my right to another point in front of the first
point.
\sect{Vague intervals and non-specific tenses}
What is the significance of failing to specify an interval
size of the type discussed in \sectref{10.5}? The
Lojban rule is that if no interval size is given, the size of
the space or time interval is left vague by the speaker. For
example:
\begin{example}
mi pu klama le zarci\n
I \optional{past} go-to the market.
\end{example}
{\noindent}really means:
\begin{description}
\item[] At a moment in the past, and possibly other moments as well, the event \q{I went to the market} was in progress.
\end{description}
The vague or unspecified interval contains an instant in the
speaker's past. However, there is no indication whether or not
the whole interval is in the speaker's past! It is entirely
possible that the interval during which the going-to-the-market
is happening stretches into the speaker's present or even
future.
\exref{10.6.1} points up a fundamental
difference between Lojban tenses and English tenses. An English
past-tense sentence like \q{I went to the market} generally
signifies that the going-to-the-market is entirely in the past;
that is, that the event is complete at the time of speaking.
Lojban \q{pu} has no such implication.
This property of a past tense is sometimes called
\q{aorist}, in reference to a similar concept in the tense
system of Classical Greek. All of the Lojban tenses have the
same property, however:
\begin{example}
le tricu ba crino\n
the tree \optional{future} is-green\n
The tree will be green.
\end{example}
{\noindent}does not imply (as the colloquial English translation does)
that the tree is not green now. The vague interval throughout
which the tree is, in fact, green may have already started.
This general principle does not mean that Lojban has no way
of indicating that a tree will be green but is not yet green.
Indeed, there are several ways of expressing that concept: see \sectref{10.10} (event contours) and \sectref{10.20} (logical connection between
tenses).
\sect{Dimensionality: VIhA}
The following cmavo are discussed in this section:
vi'i VIhA on a line
vi'a VIhA in an area
vi'u VIhA through a volume
vi'e VIhA throughout a space/time interval
The cmavo of ZEhA are sufficient to express time intervals. One
fundamental difference between space and time, however, is that
space is multi-dimensional. Sometimes we want to say not only
that something moves over a small interval, but also perhaps
that it moves in a line. Lojban allows for this. I can specify
that a motion \q{in a small space} is more specifically ``in a
short line'', \q{in a small area}, or ``through a small
volume''.
What about the child walking on the ice in \exref{10.5.1} through hyperref[ex:10:5:3]{5.3}? Given the nature of ice, probably the
area interpretation is most sensible. I can make this
assumption explicit with the appropriate member of selma'o
VIhA:
\begin{example}
le verba ve'a vi'a\n
\T cadzu le bisli\n
The child \optional{medium space interval} [2-dimensional]\n
\T walks-on the ice.\n
In a medium-sized area, the child walks on the ice.
\end{example}
Space intervals can contain either VEhA or VIhA or both, but if
both, VEhA must come first, as \exref{10.7.1}
shows.
The reader may wish to raise a philosophical point here.
(Readers who don't wish to, should skip this paragraph.) The
ice may be two-dimensional, or more accurately its surface may
be, but since the child is three-dimensional, her walking must
also be. The subjective nature of Lojban tense comes to the
rescue here: the action is essentially planar, and the third
dimension of height is simply irrelevant to walking. Even
walking on a mountain could be called \q{vi'a}, because
relatively speaking the mountain is associated with an
essentially two-dimensional surface. Motion which is not
confined to such a surface (e.g., flying, or walking through a
three-dimensional network of tunnels, or climbing among
mountains rather than on a single mountain) would be properly
described with \q{vi'u}. So the cognitive, rather than the
physical, dimensionality controls the choice of VIhA cmavo.
VIhA has a member \q{vi'e} which indicates a 4-dimensional
interval, one that involves both space and time. This allows
the spatial tenses to invade, to some degree, the temporal
tenses; it is possible to make statements about space-time
considered as an Einsteinian whole. (There are presently no
cmavo of FAhA assigned to \q{pastward} and \q{futureward}
considered as space rather than time directions --- they could
be added, though, if Lojbanists find space-time expression
useful.) If a temporal tense cmavo is used in the same tense
construct with a \q{vi'e} interval, the resulting tense may be
self-contradictory.
\sect{Movement in space: MOhI}
The following cmavo is discussed in this section:
mo'i MOhI movement flag
All the information carried by the tense constructs so far
presented has been presumed to be static: the bridi is
occurring somewhere or other in space and time, more or less
remote from the speaker. Suppose the truth of the bridi itself
depends on the result of a movement, or represents an action
being done while the speaker is moving? This too can be
represented by the tense system, using the cmavo \q{mo'i} (of
selma'o MOhI) plus a spatial direction and optional distance;
the direction now refers to a direction of motion rather than a
static direction from the speaker.
\begin{example}
le verba mo'i ri'u cadzu le bisli\n
The child \optional{movement} [right] walks-on the ice.\n
The child walks toward my right on the ice.
\end{example}
This is quite different from:
\begin{example}
le verba ri'u cadzu le bisli\n
The child \optional{right} walks-on the ice.\n
To the right of me, the child walks on the ice.
\end{example}
In either case, however, the reference frame for defining
\q{right} and \q{left} is the speaker's, not the child's. This
can be changed thus:
\begin{example}
le verba mo'i ri'u cadzu le bisli\n
\T ma'i vo'a\n
The child \optional{movement} [right] walks on the ice\n
\T in-reference-frame the-$x_1$-place.\n
The child walks toward her right on the ice.
\end{example}
\exref{10.8.3} is analogous to \exref{10.8.1}. The cmavo \q{ma'i} belongs to
selma'o BAI (explained in \chapref{9}),
and allows specifying a reference frame.
Both a regular and a \q{mo'i}-flagged spatial tense can be
combined, with the \q{mo'i} construct coming last:
\begin{example}
le verba zu'avu mo'i ri'uvi\n
\T cadzu le bisli\n
The child \optional{left} [long] [movement] [right] [short]\n
\T walks-on the ice.\n
Far to the left of me, the child walks a short\n
\T distance toward my right on the ice.
\end{example}
It is not grammatical to use multiple directions like ``zu'a
ca'u'' after \q{mo'i}, but complex movements can be expressed
in a separate bridi.
Here is an example of a movement tense on a bridi not
inherently involving movement:
\begin{example}
mi mo'i ca'uvu citka le mi sanmi\n
I \optional{movement} [front] [long] eat my meal.\n
While moving a long way forward, I eat my meal.
\end{example}
(Perhaps I am eating in an airplane.)
There is no parallel facility in Lojban at present for
expressing movement in time --- time travel --- but one could
be added easily if it ever becomes useful.
\sect{Interval properties: TAhE and \q{roi}
}
The following cmavo are discussed in this section:
di'i TAhE regularly
na'o TAhE typically
ru'i TAhE continuously
ta'e TAhE habitually
di'inai TAhE irregularly
na'onai TAhE atypically
ru'inai TAhE intermittently
ta'enai TAhE contrary to habit
roi ROI \q{n} times
roinai ROI other than \q{n} times
ze'e ZEhA whole time interval
ve'e VEhA whole space interval
Consider Lojban bridi which express events taking place in
time. Whether a very short interval (a point) or a long
interval of time is involved, the event may not be spread
consistently throughout that interval. Lojban can use the cmavo
of selma'o TAhE to express the idea of continuous or
non-continuous actions.
\begin{example}
mi puzu ze'u\n
\T velckule\n
I \optional{past} [long distance] [long interval]\n
\T am-a-school-attendee (pupil).\n
Long ago I attended school for a long time.
\end{example}
{\noindent}probably does not mean that I attended school continuously
throughout the whole of that long-ago interval. Actually, I
attended school every day, except for school holidays. More
explicitly,
\begin{example}
mi puzu ze'u di'i\n
\T velckule\n
I \optional{past} [long distance] [long interval] [regularly]\n
\T am-a-pupil.\n
Long ago I regularly attended school for a long time.
\end{example}
The four TAhE cmavo are differentiated as follows: \q{ru'i}
covers the entirety of the interval, \q{di'i} covers the parts
of the interval which are systematically spaced subintervals;
\q{na'o} covers part of the interval, but exactly which part is
determined by context; \q{ta'e} covers part of the interval,
selected with reference to the behavior of the actor (who
often, but not always, appears in the $x_1$ place of the bridi).
Using TAhE does not require being so specific. Either the
time direction or the time interval or both may be omitted (in
which case they are vague). For example:
\begin{example}
mi ba ta'e klama le zarci\n
I \optional{future} [habitually] go-to the market.\n
I will habitually go to the market.\n
I will make a habit of going to the market.
\end{example}
{\noindent}specifies the future, but the duration of the interval is
indefinite. Similarly,
\begin{example}
mi na'o klama le zarci\n
I \optional{typically} go-to the market\n
I typically go/went/will go to the market
\end{example}
{\noindent}illustrates an interval property in isolation. There are no
distance or direction cmavo, so the point of time is vague;
likewise, there is no interval cmavo, so the length of the
interval during which these goings-to-the-market take place is
also vague. As always, context will determine these vague
values.
\q{Intermittently} is the polar opposite notion to
\q{continuously}, and is expressed not with its own cmavo, but
by adding the negation suffix \q{-nai} (which belongs to
selma'o NAI) to \q{ru'i}. For example:
\begin{example}
le verba ru'inai cadzu le bisli\n
The child \optional{continuously-not} walks-on the ice.\n
The child intermittently walks on the ice.
\end{example}
As shown in the cmavo table above, all the cmavo of TAhE may be
negated with \q{-nai}; \q{ru'inai} and \q{di'inai} are probably
the most useful.
An intermittent event can also be specified by counting the
number of times during the interval that it takes place. The
cmavo \q{roi} (which belongs to selma'o ROI) can be appended to
a number to make a quantified tense. Quantified tenses are
common in English, but not so commonly named: they are
exemplified by the adverbs \q{never}, \q{once}, \q{twice},
\q{thrice}, ... \q{always}, and by the related phrases ``many
times'', \q{a few times}, \q{too many times}, and so on. All of
these are handled in Lojban by a number plus \q{-roi}:
\begin{example}
mi paroi klama le zarci\n
I \optional{one time} go-to the market.\n
I go to the market once.
\end{example}
\begin{example}
mi du'eroi klama le zarci\n
I \optional{too-many times} go-to the market.\n
I go to the market too often.
\end{example}
With the quantified tense alone, we don't know whether the
past, the present, or the future is intended, but of course the
quantified tense need not stand alone:
\begin{example}
mi pu reroi klama le zarci\n
I \optional{past} [two times] go-to the market.\n
I went to the market twice.
\end{example}
The English is slightly over-specific here: it entails that
both goings-to- the-market were in the past, which may or may
not be true in the Lojban sentence, since the implied interval
is vague. Therefore, the interval may start in the past but
extend into the present or even the future.
Adding \q{-nai} to \q{roi} is also permitted, and has the
meaning \q{other than (the number specified)}:
\begin{example}
le ratcu reroinai citka le cirli\n
The rat \optional{twice-not} eats the cheese.\n
The rat eats the cheese other than twice
\end{example}
This may mean that the rat eats the cheese fewer times, or
more times, or not at all.
It is necessary to be careful with sentences like \exref{10.9.6} and \exref{10.9.8}, where a quantified tense appears without an interval.
What \exref{10.9.8} really says is that during
an interval of unspecified size, at least part of which was set
in the past, the event of my going to the market happened
twice. The example says nothing about what happened outside
that vague time interval. This is often less than we mean. If
we want to nail down that I went to the market once and only
once, we can use the cmavo \q{ze'e} which represents the
\q{whole time interval}: conceptually, an interval which
stretches from time's beginning to its end:
\begin{example}
mi ze'e paroi klama le zarci\n
I \optional{whole interval} [once] go-to the market.
\end{example}
Since specifying no ZEhA leaves the interval vague, \exref{10.9.8} might in appropriate context mean
the same as \exref{10.9.10} after all --- but\exref{10.9.10} allows us to be specific when
specificity is necessary.
A PU cmavo following \q{ze'e} has a slightly different
meaning from one that follows another ZEhA cmavo. The compound
cmavo \q{ze'epu} signifies the interval stretching from the
infinite past to the reference point (wherever the imaginary
journey has taken you); \q{ze'eba} is the interval stretching
from the reference point to the infinite future. The remaining
form, \q{ze'eca}, makes specific the \q{whole of time}
interpretation just given. These compound forms make it
possible to assert that something has never happened without
asserting that it never will.
\begin{example}
mi ze'epu noroi klama le zarci\n
I \optional{whole interval} [past] [never] go-to the market.\n
I have never gone to the market.
\end{example}
{\noindent}says nothing about whether I might go in future.
The space equivalent of \q{ze'e} is \q{ve'e}, and it can be
used in the same way with a quantified space tense: see \sectref{10.11} for an explanation of space interval
modifiers.
\sect{Event contours: ZAhO and \q{re'u}
}
The following cmavo are discussed in this section:
pu'o ZAhO inchoative
ca'o ZAhO continuitive
ba'o ZAhO perfective
co'a ZAhO initiative
co'u ZAhO cessitive
mo'u ZAhO completitive
za'o ZAhO superfective
co'i ZAhO achievative
de'a ZAhO pausative
di'a ZAhO resumptive
re'u ROI ordinal tense
The cmavo of selma'o ZAhO express the Lojban version of what is
traditionally called \q{aspect}. This is not a notion well
expressed by English tenses, but many languages (including
Chinese and Russian among Lojban's six source languages)
consider it more important than the specification of mere
position in time.
The \q{event contours} of selma'o ZAhO, with their bizarre
keywords, represent the natural portions of an event considered
as a process, an occurrence with an internal structure
including a beginning, a middle, and an end. Since the keywords
are scarcely self-explanatory, each ZAhO will be explained in
detail here. Note that from the viewpoint of Lojban syntax,
ZAhOs are interval modifiers like TAhEs or ROI compounds; if
both are found in a single tense, the TAhE/ROI comes first and
the ZAhO afterward. The imaginary journey described by other
tense cmavo moves us to the portion of the event-as-process
which the ZAhO specifies.
It is important to understand that ZAhO cmavo, unlike the
other tense cmavo, specify characteristic portions of the
event, and are seen from an essentially timeless perspective.
The \q{beginning} of an event is the same whether the event is
in the speaker's present, past, or future. It is especially
important not to confuse the speaker-relative viewpoint of the
PU tenses with the event-relative viewpoint of the ZAhO
tenses.
The cmavo \q{pu'o}, \q{ca'o}, and \q{ba'o} (etymologically
derived from the PU cmavo) refer to an event that has not yet
begun, that is in progress, or that has ended,
respectively:
\begin{example}
mi pu'o damba\n
I \optional{inchoative} fight.\n
I'm on the verge of fighting.
\end{example}
\begin{example}
la stiv. ca'o bacru\n
Steve \optional{continuitive} utters.\n
Steve continues to talk.
\end{example}
\begin{example}
le verba ba'o cadzu le bisli\n
The child \optional{perfective} walks-on the ice.\n
The child is finished walking on the ice.
\end{example}
As discussed in \sectref{10.6}, the simple PU
cmavo make no assumptions about whether the scope of a past,
present, or future event extends into one of the other tenses
as well. \exref{10.10.1} through hyperref[ex:10:10:3]{10.3} illustrate that these ZAhO cmavo do make
such assumptions possible: the event in 10.1 has not yet begun,
definitively; likewise, the event in 10.3 is definitely over.
Note that in \exref{10.10.1} and \exref{10.10.3}, \q{pu'o} and \q{ba'o} may
appear to be reversed: \q{pu'o}, although etymologically
connected with \q{pu}, is referring to a future event; whereas
\q{ba'o}, connected with \q{ba}, is referring to a past event.
This is the natural result of the event-centered view of ZAhO
cmavo. The inchoative, or \q{pu'o}, part of an event, is in the
\q{pastward} portion of that event, when seen from the
perspective of the event itself. It is only by inference that
we suppose that \exref{10.10.1} refers to the
speaker's future: in fact, no PU tense is given, so the
inchoative part of the event need not be coincident with the
speaker's present: \q{pu'o} is not necessarily, though in fact
often is, the same as \q{ca pu'o}.
The cmavo in \exref{10.10.1} through hyperref[ex:10:10:3]{10.3} refer to spans of time. There are also
two points of time that can be usefully associated with an
event: the beginning, marked by \q{co'a}, and the end, marked
by \q{co'u}. Specifically, \q{co'a} marks the boundary between
the \q{pu'o} and \q{ca'o} parts of an event, and \q{co'u} marks
the boundary between the \q{ca'o} and \q{ba'o} parts:
\begin{example}
mi ba co'a citka le mi sanmi\n
I \optional{future} [initiative] eat my meal.\n
I will begin to eat my meal.
\end{example}
\begin{example}
mi pu co'u citka le mi sanmi\n
I \optional{past} [cessitive] eat my meal.\n
I ceased eating my meal.
\end{example}
Compare \exref{10.10.4} with:
\begin{example}
mi ba di'i co'a bajra\n
I \optional{future} [regularly] [initiative] run.\n
I will regularly begin to run.
\end{example}
{\noindent}which illustrates the combination of a TAhE with a ZAhO.
A process can have two end points, one reflecting the
\q{natural end} (when the process is complete) and the other
reflecting the \q{actual stopping point} (whether complete or
not). \exref{10.10.5} may be contrasted
with:
\begin{example}
mi pu mo'u citka le mi sanmi\n
I \optional{past} [completitive] eat my meal.\n
I finished eating my meal.
\end{example}
In \exref{10.10.7}, the meal has reached
its natural end; in \exref{10.10.5}, the meal
has merely ceased, without necessarily reaching its natural
end.
A process such as eating a meal does not necessarily proceed
uninterrupted. If it is interrupted, there are two more
relevant point events: the point just before the interruption,
marked by \q{de'a}, and the point just after the interruption,
marked by \q{di'a}. Some examples:
\begin{example}
mi pu de'a citka le mi sanmi\n
I \optional{past} [pausative] eat my meal.\n
I stopped eating my meal\n
\T (with the intention of resuming).
\end{example}
\begin{example}
mi ba di'a citka le mi sanmi\n
I \optional{future} [resumptive] eat my meal.\n
I will resume eating my meal.
\end{example}
In addition, it is possible for a process to continue beyond
its natural end. The span of time between the natural and the
actual end points is represented by \q{za'o}:
\begin{example}
le xirma ca za'o\n
\T jivna bajra\n
The horse \optional{present} [superfective]\n
\T compete-type-of runs.\n
The horse keeps on running a race too long.
\end{example}
{\noindent}which means that it ran past the finish line (after the race
was over --- in most races, the runners do not stop right at
the finish line).
An entire event can be treated as a single moment using the
cmavo \q{co'i}:
\begin{example}
la djan. pu co'i catra la djim\n
John \optional{past} [achievative] kills Jim.\n
John was at the point in time where he killed Jim.
\end{example}
Finally, since an activity is cyclical, an individual cycle can
be referred to using a number followed by \q{re'u}, which is
the other cmavo of selma'o ROI:
\begin{example}
mi pare'u klama le zarci\n
I \optional{first time} go-to the store.\n
I go to the store for the first time\n
\T (within a vague interval).
\end{example}
Note the difference between:
\begin{example}
mi pare'u paroi klama le zarci\n
I \optional{first time} [one time] go-to the store.\n
For the first time, I go to the store once.
\end{example}
{\noindent}and
\begin{example}
mi paroi pare'u klama le zarci\n
I \optional{one time} [first time] go-to the store.\n
There is one occasion on which I go to\n
\T the store for the first time.
\end{example}
\sect{Space interval modifiers: FEhE}
The following cmavo is discussed in this section:
fe'e FEhE space interval modifier flag
Like time intervals, space intervals can also be continuous,
discontinuous, or repetitive. Rather than having a whole
separate set of selma'o for space interval properties, we
instead prefix the flag \q{fe'e} to the cmavo used for time
interval properties. A space interval property would be placed
just after the space interval size and/or dimensionality cmavo:
\begin{example}
ko vi'i fe'e di'i\n
\T sombo le gurni\n
You-imperative \optional{1-dimensional} [space:] [regularly]\n
\T sow the grain.\n
Sow the grain in a line and evenly!
\end{example}
\begin{example}
mi fe'e ciroi\n
\T tervecnu lo selsalta\n
I \optional{space:} [three places]\n
\T buy those-which-are salad-ingredients.\n
I buy salad ingredients in three locations.
\end{example}
\begin{example}
ze'e roroi ve'e\n
\T fe'e roroi ku\n
\T li re su'i re du li vo\n
\optional{whole time} [all times] [whole space]\n
\T [space:] [all places]\n
\T The-number 2 + 2 = the-number 4.\n
Always and everywhere, two plus two is four.
\end{example}
As shown in \exref{10.11.3}, when a tense
comes first in a bridi, rather than in its normal position
before the selbri (in this case \q{du}), it is emphasized.
The \q{fe'e} marker can also be used for the same purpose
before members of ZAhO. (The cmavo \q{be'a} belongs to selma'o
FAhA; it is the space direction meaning \q{north of}.)
\begin{example}
tu ve'abe'a\n
\T fe'e co'a rokci\n
that-yonder \optional{medium space interval - north}\n
\T [space] [initiative] is-a-rock.\n
That is the beginning of a rock extending to my north.\n
That is the south face of a rock.
\end{example}
Here the notion of a \q{beginning point} represented by the
cmavo \q{co'a} is transferred from \q{beginning in time} to
\q{beginning in space} under the influence of the \q{fe'e}
flag. Space is not inherently oriented, unlike time, which
flows from past to future: therefore, some indication of
orientation is necessary, and the \q{ve'abe'a} provides an
orientation in which the south face is the \q{beginning} and
the north face is the \q{end}, since the rock extends from
south (near me) to north (away from me).
Many natural languages represent time by a space-based
metaphor: in English, what is past is said to be \q{behind us}.
In other languages, the metaphor is reversed. Here, Lojban is
representing space (or space interval modifiers) by a
time-based metaphor: the choice of a FAhA cmavo following a
VEhA cmavo indicates which direction is mapped onto the future.
(The choice of future rather than past is arbitrary, but
convenient for English-speakers.)
If both a TAhE (or ROI) and a ZAhO are present as space
interval modifiers, the \q{fe'e} flag must be prefixed to
each.
\sect{Tenses as sumti tcita}
So far, we have seen tenses only just before the selbri, or
(equivalently in meaning) floating about the bridi with \q{ku}.
There is another major use for tenses in Lojban: as sumti
tcita, or argument tags. A tense may be used to add spatial or
temporal information to a bridi as, in effect, an additional
place:
\begin{example}
mi klama le zarci ca le nu\n
\T do klama le zdani\n
I go-to the market \optional{present} the event-of\n
\T you go-to the house.\n
I go to the market when you go to the house.
\end{example}
Here \q{ca} does not appear before the selbri, nor with \q{ku};
instead, it governs the following sumti, the \q{le nu}
construct. What \exref{10.12.1} asserts is
that the action of the main bridi is happening at the same time
as the event mentioned by that sumti. So \q{ca}, which means
\q{now} when used with a selbri, means \q{simultaneously-with}
when used with a sumti. Consider another example:
\begin{example}
mi klama le zarci pu le nu\n
\T do pu klama le zdani\n
I go-to the market \optional{past} the event-of\n
\T you [past] go-to the house.
\end{example}
The second \q{pu} is simply the past tense marker for the
event of your going to the house, and says that this event is
in the speaker's past. How are we to understand the first
\q{pu}, the sumti tcita?
All of our imaginary journeys so far have started at the
speaker's location in space and time. Now we are specifying an
imaginary journey that starts at a different location, namely
at the event of your going to the house. \exref{10.12.2} then says that my going to the
market is in the past, relative not to the speaker's present
moment, but instead relative to the moment when you went to the
house. \exref{10.12.2} can therefore be
translated:
\begin{description}
\item[] I had gone to the market before you went to the house.
\end{description}
(Other translations are possible, depending on the ever-present
context.) Spatial direction and distance sumti tcita are
exactly analogous:
\begin{example}
le ratcu cu citka le cirla vi le panka\n
The rat eats the cheese \optional{short distance} the park.\n
The rat eats the cheese near the park.
\end{example}
\begin{example}
le ratcu cu citka le cirla\n
\T vi le vu panka\n
The rat eats the cheese\n
\T \optional{short distance} the [long distance] park\n
The rat eats the cheese near the faraway park.
\end{example}
\begin{example}
le ratcu cu citka le cirla\n
\T vu le vi panka\n
The rat eats the cheese\n
\T \optional{long distance} the [short distance] park\n
The rat eats the cheese far away from the nearby park.
\end{example}
The event contours of selma'o ZAhO (and their space
equivalents, prefixed with \q{fe'e}) are also useful as sumti
tcita. The interpretation of ZAhO tcita differs from that of
FAhA, VA, PU, and ZI tcita, however. The event described in the
sumti is viewed as a process, and the action of the main bridi
occurs at the phase of the process which the ZAhO specifies, or
at least some part of that phase. The action of the main bridi
itself is seen as a point event, so that there is no issue
about which phase of the main bridi is intended. For example:
\begin{example}
mi morsi ba'o le nu mi jmive\n
I am-dead \optional{perfective} the event-of I live.\n
I die in the aftermath of my living.
\end{example}
Here the (point-)event of my being dead is the portion of my
living-process which occurs after the process is complete.
Contrast \exref{10.12.6} with:
\begin{example}
mi morsi ba le nu mi jmive\n
I am-dead \optional{future} the event-of I live.
\end{example}
As explained in \sectref{10.6}, \exref{10.12.7} does not exclude the possibility
that I died before I ceased to live!
Likewise, we might say:
\begin{example}
mi klama le zarci pu'o le nu mi citka\n
I go-to the store \optional{inchoative} the event-of I eat
\end{example}
{\noindent}which indicates that before my eating begins, I go to the
store, whereas
\begin{example}
mi klama le zarci ba'o le nu mi citka\n
I go-to the store \optional{perfective} the event-of I eat
\end{example}
{\noindent}would indicate that I go to the store after I am finished
eating.
Here is an example which mixes temporal ZAhO (as a tense)
and spatial ZAhO (as a sumti tcita):
\begin{example}
le bloti pu za'o xelklama\n
\T fe'e ba'o le lalxu\n
the boat \optional{past} [superfective]\n
\T is-a-transport-mechanism\n
\T [space] [perfective] the lake.\n
The boat sailed for too long and beyond the lake.
\end{example}
Probably it sailed up onto the dock. One point of
clarification: although \q{xelklama} appears to mean simply
\q{is-a-mode-of-transport}, it does not -- the bridi of \exref{10.12.10} has four omitted arguments,
and thus has the (physical) journey which goes on too long as
part of its meaning.
The remaining tense cmavo, which have to do with interval
size, dimension, and continuousness (or lack thereof) are
interpreted to let the sumti specify the particular interval
over which the main bridi operates:
\begin{example}
mi klama le zarci reroi le ca djedi\n
I go-to the market \optional{twice} the [present] day\n
I go/went/will go to the market twice today.
\end{example}
Be careful not to confuse a tense used as a sumti tcita with a
tense used within a seltcita sumti:
\begin{example}
loi snime cu carvi\n
\T ze'u le ca dunra\n
some-of-the-mass-of snow rains\n
\T \optional{long time interval} the [present] winter.\n
Snow falls during this winter.
\end{example}
{\noindent}claims that the interval specified by \q{this winter} is long,
as events of snowfall go, whereas
\begin{example}
loi snime cu carvi\n
\T ca le ze'u dunra\n
some-of-the-mass-of snow rains\n
\T \optional{present} the [long time] winter.\n
Snow falls in the long winter.
\end{example}
{\noindent}claims that during some part of the winter, which is long as
winters go, snow falls.
\sect{Sticky and multiple tenses: KI}
The following cmavo is discussed in this section:
ki KI sticky tense set/reset
So far we have only considered tenses in isolated bridi. Lojban
provides several ways for a tense to continue in effect over
more than a single bridi. This property is known as
\q{stickiness}: the tense gets \q{stuck} and remains in effect
until explicitly \q{unstuck}. In the metaphor of the imaginary
journey, the place and time set by a sticky tense may be
thought of as a campsite or way-station: it provides a
permanent origin with respect to which other tenses are
understood. Later imaginary journeys start from that point
rather than from the speaker.
To make a tense sticky, suffix \q{ki} to it:
\begin{example}
mi puki klama le zarci\n
\T .i le nanmu cu batci le gerku\n
I \optional{past} [sticky] go-to the market.\n
\T The man bites the dog.\n
I went to the market. The man bit the dog.
\end{example}
Here the use of \q{puki} rather than just \q{pu} ensures
that the tense will affect the next sentence as well.
Otherwise, since the second sentence is tenseless, there would
be no way of determining its tense; the event of the second
sentence might happen before, after, or simultaneously with
that of the first sentence.
(The last statement does not apply when the two sentences
form part of a narrative. See \sectref{10.14} for
an explanation of \q{story time}, which employs a different set
of conventions.)
What if the second sentence has a tense anyway?
\begin{example}
mi puki klama le zarci\n
\T .i le nanmu pu batci le gerku\n
I \optional{past} sticky go-to the market.\n
\T The man [past] bites the dog.
\end{example}
Here the second \q{pu} does not replace the sticky tense,
but adds to it, in the sense that the starting point of its
imaginary journey is taken to be the previously set sticky
time. So the translation of \exref{10.13.2}
is:
\begin{example}
I went to the market.\n
\T The man had earlier bitten the dog.
\end{example}
{\noindent}and it is equivalent in meaning (when considered in isolation
from any other sentences) to:
\begin{example}
mi pu klama le zarci\n
\T .i le nanmu pupu batci le gerku\n
I \optional{past} go-to the market.\n
\T The man [past] [past] bites the dog.
\end{example}
The point has not been discussed so far, but it is perfectly
grammatical to have more than one tense construct in a
sentence:
\begin{example}
puku mi ba klama le zarci\n
\optional{past} I [future] go-to the market.\n
Earlier, I was going to go to the market.
\end{example}
Here there are two tenses in the same bridi, the first
floating free and specified by \q{puku}, the second in the
usual place and specified by \q{ba}. They are considered
cumulative in the same way as the two tenses in separate
sentences of \exref{10.13.4}. \exref{10.13.5} is therefore equivalent in
meaning, except for emphasis, to:
\begin{example}
mi puba klama le zarci\n
I \optional{past} [future] go-to the market.\n
I was going to go to the market.
\end{example}
Compare \exref{10.13.7} and \exref{10.13.8}, which have a different meaning
from \exref{10.13.5} and \exref{10.13.6}:
\begin{example}
mi ba klama le zarci puku\n
I \optional{future} go-to the market [past].\n
I will have gone to the market earlier.
\end{example}
\begin{example}
mi bapu klama le zarci\n
I \optional{future} [past] go-to the market.\n
I will have gone to the market.
\end{example}
So when multiple tense constructs in a single bridi are
involved, order counts --- the tenses cannot be shifted around
as freely as if there were only one tense to worry about.
But why bother to allow multiple tense constructs at all?
They specify separate portions of the imaginary journey, and
can be useful in order to make part of a tense sticky. Consider\exref{10.13.9}, which adds a second bridi
and a \q{ki} to \exref{10.13.5}:
\begin{description}
\item[13.9] pukiku mi ba klama le zarci .i le nanmu cu batci le gerku [past] [sticky] I [future] go-to the market. The man bites the dog.
\end{description}
What is the implied tense of the second sentence? Not
\q{puba}, but only \q{pu}, since only \q{pu} was made sticky
with \q{ki}. So the translation is:
\begin{description}
\item[] I was going to go to the market. The man bit the dog.
\end{description}
Lojban has several ways of embedding a bridi within another
bridi: descriptions, abstractors, relative clauses.
(Technically, descriptions contain selbri rather than bridi.)
Any of the selbri of these subordinate bridi may have tenses
attached. These tenses are interpreted relative to the tense of
the main bridi:
\begin{example}
mi pu klama le ba'o zarci\n
I \optional{past} go-to the [perfective] market\n
I went to the former market.
\end{example}
The significance of the \q{ba'o} in \exref{10.13.10} is that the speaker's
destination is described as being ``in the aftermath of being a
market''; that is, it is a market no longer. In particular, the
time at which it was no longer a market is in the speaker's
past, because the \q{ba'o} is interpreted relative to the
\q{pu} tense of the main bridi.
Here is an example involving an abstraction bridi:
\begin{example}
mi ca jinvi le du'u mi ba morsi\n
I now opine the fact-that I will-be dead.\n
I now believe that I will be dead.
\end{example}
Here the event of being dead is said to be in the future
with respect to the opinion, which is in the present.
\q{ki} may also be used as a tense by itself. This cancels
all stickiness and returns the bridi and all following bridi to
the speaker's location in both space and time:
\begin{example}
mi ki cusku dei\n
I \optional{here and now} express this-utterance.\n
I say this sentence now.
\end{example}
In complex descriptions, multiple tenses may be saved and then
used by adding a subscript to \q{ki}. A time made sticky with
\q{kixipa} (ki-sub-1) can be returned to by specifying
\q{kixipa} as a tense by itself. In the case of written
expression, the writer's here-and-now is often different from
the reader's, and a pair of subscripted \q{ki} tenses could be
used to distinguish the two.
\sect{Story time}
Making strict use of the conventions explained in \sectref{10.13} would be intolerably awkward when a
story is being told. The time at which a story is told by the
narrator is usually unimportant to the story. What matters is
the flow of time within the story itself. The term \q{story} in
this section refers to any series of statements related in
more-or-less time-sequential order, not just a fictional
one.
Lojban speakers use a different set of conventions, commonly
called \q{story time}, for inferring tense within a story. It
is presumed that the event described by each sentence takes
place some time more or less after the previous ones.
Therefore, tenseless sentences are implicitly tensed as ``what
happens next''. In particular, any sticky time setting is
advanced by each sentence.
The following mini-story illustrates the important features
of story time. A sentence-by-sentence explication follows:
\begin{example}
puzuki ku ne'iki le kevna\n
\T le ninmu goi ko'a zutse le rokci\n
\optional{past} [long] [sticky] [,] [inside] [sticky] the cave,\n
\T the woman defined-as she-1 sat-on the rock\n
Long ago, in a cave, a woman sat on a rock.
\end{example}
\begin{example}
.i ko'a citka loi kanba rectu\n
She-1 \optional{tenseless} eat some-of-the-mass-of goat flesh.\n
She was eating goat's meat.
\end{example}
\begin{example}
.i ko'a pu jukpa ri le mudyfagri\n
She \optional{past} cook the-last-mentioned\n
\T by-method the wood-fire.\n
She had cooked the meat over a wood fire.
\end{example}
\begin{example}
.i lei rectu cu zanglare\n
The-mass-of flesh is-(favorable)-warm.\n
The meat was pleasantly warm.
\end{example}
\begin{example}
.i le labno goi ko'e bazaki\n
\T nenri klama le kevna\n
The wolf defined-as it-2 \optional{future} [medium] [sticky]\n
\T within-came to-the cave.\n
A while later, a wolf came into the cave.
\end{example}
\begin{example}
.i ko'e lebna lei rectu ko'a\n
It-2 \optional{tenseless} takes the-mass-of flesh from-her-1.\n
It took the meat from her.
\end{example}
\begin{example}
.i ko'e bartu klama\n
It-2 out ran\n
It ran out.
\end{example}
\exref{10.14.1} sets both the time (long ago)
and the place (in a cave) using \q{ki}, just like the sentence
sequences in \sectref{10.13}. No further space
cmavo are used in the rest of the story, so the place is
assumed to remain unchanged. The English translation of \exref{10.14.1} is marked for past tense also,
as the conventions of English storytelling require:
consequently, all other English translation sentences are also
in the past tense. (We don't notice how strange this is; even
stories about the future are written in past tense!) This
conventional use of past tense is not used in Lojban
narratives.
\exref{10.14.2} is tenseless. Outside
story time, it would be assumed that its event happens
simultaneously with that of \exref{10.14.1},
since a sticky tense is in effect; the rules of story time,
however, imply that the event occurs afterwards, and that the
story time has advanced (changing the sticky time set in \exref{10.14.1}).
\exref{10.14.3} has an explicit tense.
This is taken relative to the latest setting of the sticky
time; therefore, the event of \exref{10.14.3}
happens before that of \exref{10.14.2}. It
cannot be determined if \exref{10.14.3}
happens before or after \exref{10.14.1}.
\exref{10.14.4} is again tenseless. Story
time was not changed by the flashback in \exref{10.14.3}, so \exref{10.14.4} happens after \exref{10.14.2}.
\exref{10.14.5} specifies the future
(relative to \exref{10.14.4}) and makes it
sticky. So all further events happen after \exref{10.14.5}.
\exref{10.14.6} and \exref{10.14.7} are again tenseless, and so
happen after \exref{10.14.5}. (Story time is
changed.)
So the overall order is 14.1 - 14.3 - 14.2 - 14.4 - (medium
interval) - 14.5 - 14.6 - 14.7. It is also possible that 14.3
happens before 14.1.
If no sticky time (or space) is set initially, the story is
set at an unspecified time (or space): the effect is like that
of choosing an arbitrary reference point and making it sticky.
This style is common in stories that are jokes. The same
convention may be used if the context specifies the sticky time
sufficiently.
\sect{Tenses in subordinate bridi}
English has a set of rules, formally known as ``sequence of
tense rules'', for determining what tense should be used in a
subordinate clause, depending on the tense used in the main
sentence. Here are some examples:
\begin{example}
John says that George is going to the market.
\end{example}
\begin{example}
John says that George went to the market.
\end{example}
\begin{example}
John said that George went to the market.
\end{example}
\begin{example}
John said that George had gone to the market.
\end{example}
In \exref{10.15.1} and \exref{10.15.2}, the tense of the main sentence
is the present: \q{says}. If George goes when John speaks, we
get the present tense \q{is going} (\q{goes} would be
unidiomatic); if George goes before John speaks, we get the
past tense \q{went}. But if the tense of the main sentence is
the past, with \q{said}, then the tense required in the
subordinate clause is different. If George goes when John
speaks, we get the past tense \q{went}; if George goes before
John speaks, we get the past-perfect tense \q{had gone}.
The rule of English, therefore, is that both the tense of
the main sentence and the tense of the subordinate clause are
understood relative to the speaker (not John, but the person
who speaks \exref{10.15.1} through hyperref\optional{ex:10:15:4}{15.4}).
Lojban, like Russian and Esperanto, uses a different
convention. A tense in a subordinate bridi is understood to be
relative to the tense already set in the main bridi. Thus \exref{10.15.1} through hyperref[ex:10:15:4]{15.4} can be expressed in Lojban respectively
thus:
\begin{example}
la djan. ca cusku le se du'u\n
\T la djordj. ca klama le zarci\n
John \optional{present} says the statement-that\n
\T George [present] goes-to the market.
\end{example}
\begin{example}
la djan. ca cusku le se du'u\n
\T la djordj. pu klama le zarci\n
John \optional{present} says the statement-that\n
\T George [past] goes-to the market.
\end{example}
\begin{example}
la djan. pu cusku le se du'u\n
\T la djordj. ca klama le zarci\n
John \optional{past} says the statement-that\n
\T George [present] goes-to the market.
\end{example}
\begin{example}
la djan. pu cusku le se du'u\n
\T la djordj. pu klama le zarci\n
John \optional{past} says the statement-that\n
\T George [past] goes-to the market.
\end{example}
Probably the most counterintuitive of the Lojban examples is\exref{10.15.7}. The \q{ca} looks quite odd,
as if George were going to the market right now, rather than
back when John spoke. But this \q{ca} is really a \q{ca} with
respect to a reference point specified by the outer \q{pu}.
This behavior is the same as the additive behavior of multiple
tenses in the same bridi, as explained in \sectref{10.13}.
There is a special cmavo \q{nau} (of selma'o CUhE) which can
be used to override these rules and get to the speaker's
current reference point. (Yes, it sounds like English \q{now}.)
It is not grammatical to combine \q{nau} with any other cmavo
in a tense, except by way of a logical or non-logical
connection (see \sectref{10.20}). Here is a
convoluted sentence with several nested bridi which uses
\q{nau} at the lowest level:
\begin{example}
la djan. pu cusku le se du'u\n
\T la .alis pu cusku le se du'u\n
\T la djordj. pu cusku le se du'u\n
\T la maris. nau klama le zarci\n
John \optional{past} says the statement-that\n
\T Alice [past] says the statement-that\n
\T George [past] says the statement that\n
\T Mary [now] goes-to the market.\n
John said that Alice had said that George had earlier\n
\T said that Mary is now going to the market.
\end{example}
The use of \q{nau} does not affect sticky tenses.
\sect{Tense relations between sentences}
The sumti tcita method, explained in \hyperref[sec:10:12]{Section
12}, of asserting a tense relationship between two events
suffers from asymmetry. Specifically,
\begin{example}
le verba cu cadzu le bisli\n
\T zu'a le nu le nanmu cu batci le gerku\n
The child walks-on the ice\n
\T \optional{left} the event-of the man bites the dog.\n
The child walks on the ice to the left of where\n
\T the man bites the dog.
\end{example}
{\noindent}which specifies an imaginary journey leftward from the man
biting the dog to the child walking on the ice, claims only
that the child walks on the ice. By the nature of \q{le nu},
the man's biting the dog is merely referred to without being
claimed. If it seems desirable to claim both, each event can be
expressed as a main sentence bridi, with a special form of
\q{.i} connecting them:
\begin{example}
le nanmu cu batci le gerku\n
\T .izu'abo le verba cu cadzu le bisli\n
The man bites the dog.\n
\T \optional{Left} the child walks-on the ice.\n
The man bites the dog. To the left, the child\n
\T walks on the ice.
\end{example}
\q{.izu'abo} is a compound cmavo: the \q{.i} separates the
sentences and the \q{zu'a} is the tense. The \q{bo} is required
to prevent the \q{zu'a} from gobbling up the following sumti,
namely \q{le verba}.
Note that the bridi in \exref{10.16.2}
appear in the reverse order from their appearance in \exref{10.16.1}. With \q{.izu'abo} (and all
other afterthought tense connectives) the sentence specifying
the origin of the journey comes first. This is a natural order
for sentences, but requires some care when converting between
this form and the sumti tcita form.
\exref{10.16.2} means the same thing
as:
\begin{example}
le nanmu cu batci le gerku\n
\T .i zu'a la'edi'u\n
\T le verba cu cadzu le bisli\n
The man bites the dog.\n
\T \optional{Left} the-referent-of-the-last-sentence\n
\T the child walks-on the ice.\n
The man bites the dog.\n
\T Left of what I just mentioned,\n
\T the child walks on the ice.
\end{example}
If the \q{bo} is omitted, the meaning changes:
\begin{example}
le nanmu cu batci le gerku\n
\T .i zu'a le verba cu cadzu le bisli\n
The man bites the dog.\n
\T \optional{Left} the child [something] walks-on the ice.\n
The man bites the dog. To the left of the child,\n
\T something walks on the ice.
\end{example}
Here the first place of the second sentence is unspecified,
because \q{zu'a} has absorbed the sumti \q{le verba}.
Do not confuse either \exref{10.16.2} or\exref{10.16.4} with the following:
\begin{example}
le nanmu cu batci le gerku\n
\T .i zu'aku le verba cu cadzu le bisli\n
The man bites the dog.\n
\T \optional{Left} the child walks-on the ice.\n
The man bites the dog. Left of me, the child walks\n
\T on the ice.
\end{example}
In \exref{10.16.5}, the origin point is
the speaker, as is usual with \q{zu'aku}. \exref{10.16.2} makes the origin point of the
tense the event described by the first sentence.
Two sentences may also be connected in forethought by a
tense relationship. Just like afterthought tense connection,
forethought tense connection claims both sentences, and in
addition claims that the time or space relationship specified
by the tense holds between the events the two sentences
describe.
The origin sentence is placed first, preceded by a tense
plus \q{gi}. Another \q{gi} is used to separate the
sentences:
\begin{example}
pugi mi klama le zarci gi mi klama le zdani\n
\optional{past} I go-to the market [,] I go-to the house.\n
Before I go to the market, I go to the house.
\end{example}
A parallel construction can be used to express a tense
relationship between sumti:
\begin{example}
mi klama pugi le zarci gi le zdani\n
I go-to \optional{past} the market [,] the house.
\end{example}
Because English does not have any direct way of expressing a
tense-like relationship between nouns, \exref{10.16.7} cannot be expressed in English without paraphrasing it
either into \exref{10.16.6} or else into ``I
go to the house before the market'', which is ambiguous --- is
the market going?
Finally, a third forethought construction expresses a tense
relationship between bridi-tails rather than whole bridi. (The
construct known as a \q{bridi-tail} is explained fully in \chapref{14}; roughly speaking, it is a
selbri with any following sumti.) \exref{10.16.8} is equivalent in meaning to \exref{10.16.6} and \exref{10.16.7}:
\begin{example}
mi pugi klama le zarci gi klama le zdani\n
I \optional{past} go-to the market [,] go-to the house.\n
I, before going to the market, go to the house.
\end{example}
In both \exref{10.16.7} and \exref{10.16.8}, the underlying sentences ``mi
klama le zarci'' and \q{mi klama le zdani} are not claimed;
only the relationship in time between them is claimed.
Both the forethought and the afterthought forms are
appropriate with PU, ZI, FAhA, VA, and ZAhO tenses. In all
cases, the equivalent forms are (where X and Y stand for
sentences, and TENSE for a tense cmavo):
\begin{description}
\item[] subordinate: X TENSE le nu Y afterthought coordinate: Y .i+TENSE+bo X forethought coordinate: TENSE+gi X gi Y
\end{description}
\sect{Tensed logical connectives}
The Lojban tense system interacts with the Lojban logical
connective system. That system is a separate topic, explained
in \chapref{14} and touched on only in
summary here. By the rules of the logical connective system, \exref{10.17.1} through 17.3 are equivalent in
meaning:
\begin{example}
la teris. satre le mlatu\n
\T .ije la teris. satre le ractu\n
Terry strokes the cat.\n
\T And Terry strokes the rabbit.
\end{example}
\begin{example}
la teris. satre le mlatu gi'e satre le ractu\n
Terry strokes the cat and strokes the rabbit.
\end{example}
\begin{example}
la teris. satre le mlatu .e le ractu\n
Terry strokes the cat and the rabbit.
\end{example}
Suppose we wish to add a tense relationship to the logical
connective \q{and}? To say that Terry strokes the cat and later
strokes the rabbit, we can combine a logical connective with a
tense connective by placing the logical connective first, then
the tense, and then the cmavo \q{bo}, thus:
\begin{example}
la teris. satre le mlatu\n
\T .ijebabo la teris. satre le ractu\n
Terry strokes the cat.\n
\T And then Terry strokes the rabbit.
\end{example}
\begin{example}
la teris. satre le mlatu gi'ebabo satre le ractu\n
Terry strokes the cat, and then strokes the rabbit.
\end{example}
\begin{example}
la teris. satre le mlatu .ebabo le ractu\n
Terry strokes the cat and then the rabbit.
\end{example}
\exref{10.17.4} through 17.6 are equivalent
in meaning. They are also analogous to \exref{10.17.1} through hyperref\optional{ex:10:17:3}{17.3} respectively. The \q{bo} is required for
the same reason as in \exref{10.16.2}: to
prevent the \q{ba} from functioning as a sumti tcita for the
following sumti (or, in \exref{10.17.5}, from
being attached to the following selbri).
In addition to the \q{bo} construction of \exref{10.17.4} through hyperref[ex:10:17:6]{17.6},
there is also a form of tensed logical connective with ``ke ...
ke'e'' (\q{tu'e... tu'u} for sentences). The logical connective
system makes \exref{10.17.7} through hyperref[ex:10:17:9]{17.9} equivalent in meaning:
\begin{example}
mi bevri le dakli\n
\T .ije tu'e mi bevri le gerku\n
\T .ija mi bevri le mlatu tu'u\n
I carry the sack.\n
\T And (I carry the dog.\n
\T And/or I carry the cat).\n
I carry the sack. And I carry the dog, or I carry\n
\T the cat, or I carry both.
\end{example}
\begin{example}
mi bevri le dakli\n
\T gi'eke bevri le gerku gi'a bevri le mlatu\n
I carry the sack\n
\T and (carry the dog and/or carry the cat).\n
I carry the sack, and also carry the dog\n
\T or carry the cat or carry both.
\end{example}
\begin{example}
mi bevri le dakli .eke le gerku .a le mlatu\n
I carry the sack and (the dog or the cat)\n
I carry the sack and also the dog or the cat or both.
\end{example}
Note the uniformity of the Lojban, as contrasted with the
variety of ways in which the English provides for the correct
grouping. In all cases, the meaning is that I carry the sack in
any case, and either the cat or the dog or both.
To express that I carry the sack first (earlier in time),
and then the dog or the cat or both simultaneously, I can
insert tenses to form \exref{10.17.10}
through hyperref\optional{ex:10:17:12}{17.12}:
\begin{example}
mi bevri le dakli\n
\T .ije ba tu'e mi bevri le gerku\n
\T .ijacabo mi bevri le mlatu tu'u\n
I carry the sack.\n
\T And \optional{future} (I carry the dog.\n
\T And/or [present] I carry the cat.)\n
I carry the sack. And then I will carry the dog\n
\T or I will carry the cat or I will carry both\n
\T at once.
\end{example}
\begin{example}
mi bevri le dakli\n
\T gi'ebake bevri le gerku\n
\T gi'acabo bevri le mlatu\n
I carry the sack\n
\T and \optional{future} (carry the dog\n
\T and/or [present] carry the cat).\n
I carry the sack and then will carry the dog\n
\T or carry the cat or carry both at once.
\end{example}
\begin{example}
mi bevri le dakli\n
\T .ebake bevri le gerku .acabo le mlatu\n
I carry the sack and\n
\T \optional{future} (the cat and/or [present] the dog).\n
I carry the sack, and then the cat or the dog\n
\T or both at once.
\end{example}
\exref{10.17.10} through hyperref[ex:10:17:12]{17.12} are equivalent in meaning to each
other, and correspond to the tenseless \exref{10.17.7} through hyperref[ex:10:17:9]{17.9} respectively.
\sect{Tense negation}
Any bridi which involves tenses of selma'o PU, FAhA, or ZAhO
can be contradicted by a \q{-nai} suffixed to the tense cmavo.
Some examples:
\begin{example}
mi punai klama le zarci\n
I \optional{past} [not] go-to the market.\n
I didn't go to the market.
\end{example}
As a contradictory negation, \exref{10.18.1}
implies that the bridi as a whole is false without saying
anything about what is true. When the negated tense is a sumti
tcita, \q{-nai} negation indicates that the stated relationship
does not hold:
\begin{example}
mi klama le zarci canai le nu\n
\T do klama le zdani\n
I go-to the market \optional{present} [not] the event-of\n
\T you go-to the house.\n
It is not true that I went to the market at the same\n
\T time that you went to the house.
\end{example}
\begin{example}
le nanmu batci le gerku ne'inai le kumfa\n
The man bites the dog \optional{within} [not] the room.\n
The man didn't bite the dog inside the room.
\end{example}
\begin{example}
mi morsi ca'onai le nu mi jmive\n
I am-dead \optional{continuitive - negated} the event-of I live.\n
It is false that I am dead during my life.
\end{example}
It is also possible to perform scalar negation of whole tense
constructs by placing a member of NAhE before them. Unlike
contradictory negation, scalar negation asserts a truth: that
the bridi is true with some tense other than that specified.
The following examples are scalar negation analogues of \exref{10.18.1} to hyperref[ex:10:18:3]{18.3}:
\begin{example}
mi na'e pu klama le zarci\n
I \optional{non-} [past] go-to the market.\n
I go to the market other than in the past.
\end{example}
\begin{example}
le nanmu batci le gerku to'e ne'i le kumfa\n
The man bites the dog \optional{opposite-of} [within] the room.\n
The man bites the dog outside the room.
\end{example}
\begin{example}
mi klama le zarci na'e ca le nu\n
\T do klama le zdani\n
I go-to the market \optional{non-} [present] the event-of\n
\T you go-to the house.\n
I went to the market at a time other than the time at\n
\T which you went to the house.
\end{example}
\begin{example}
mi morsi na'e ca'o le nu mi jmive\n
I am-dead \optional{non-} [continuitive] the event-of I live.\n
I am dead other than during my life.
\end{example}
Unlike \q{-nai} contradictory negation, scalar negation of
tenses is not limited to PU and FAhA:
\begin{example}
le verba na'e ri'u cadzu le bisli\n
The child \optional{non-} [right] walks-on the ice\n
The child walks on the ice other than to my right.
\end{example}
The use of \q{-nai} on cmavo of TAhE and ROI has already been
discussed in \sectref{10.9}; this use is also a
scalar negation.
\sect{Actuality, potentiality, capability: CAhA}
The following cmavo are discussed in this section:
ca'a CAhA actually is
ka'e CAhA is innately capable of
nu'o CAhA can but has not
pu'i CAhA can and has
Lojban bridi without tense markers may not necessarily refer to
actual events: they may also refer to capabilities or potential
events. For example:
\begin{example}
ro datka cu flulimna\n
all ducks are-float-swimmers\n
All ducks swim by floating.
\end{example}
{\noindent}is a Lojban truth, even though the colloquial English
translation is false or at best ambiguous. This is because the
tenseless Lojban bridi doesn't necessarily claim that every
duck is swimming or floating now or even at a specific time or
place. Even if we add a tense marker to \exref{10.19.1},
\begin{example}
ro datka ca flulimna\n
all ducks \optional{present} are-float-swimmers.\n
All ducks are now swimming by floating.
\end{example}
{\noindent}the resulting \exref{10.19.2} might still be
considered a truth, even though the colloquial English seems
even more likely to be false. All ducks have the potential of
swimming even if they are not exercising that potential at
present. To get the full flavor of ``All ducks are now
swimming'', we must append a marker from selma'o CAhA to the
tense, and say:
\begin{example}
ro datka ca ca'a flulimna\n
all ducks \optional{present} [actual] are-float-swimmers\n
All ducks are now actually swimming by floating.
\end{example}
A CAhA cmavo is always placed after any other tense cmavo,
whether for time or for space. However, a CAhA cmavo comes
before \q{ki}, so that a CAhA condition can be made sticky.
\exref{10.19.3} is false in both Lojban
and English, since it claims that the swimming is an actual,
present fact, true of every duck that exists, whereas in fact
there is at least one duck that is not swimming now.
Furthermore, some ducks are dead (and therefore sink); some
ducks have just hatched (and do not know how to swim yet), and
some ducks have been eaten by predators (and have ceased to
exist as separate objects at all). Nevertheless, all these
ducks have the innate capability of swimming --- it is part of
the nature of duckhood. The cmavo \q{ka'e} expresses this
notion of innate capability:
\begin{example}
ro datka ka'e flulimna\n
all ducks \optional{capable} are-float-swimmers.\n
All ducks are innately capable of swimming.
\end{example}
Under some epistemologies, innate capability can be extended in
order to apply the innate properties of a mass to which certain
individuals belong to the individuals themselves, even if those
individuals are themselves not capable of fulfilling the claim
of the bridi. For example:
\begin{example}
la djan. ka'e viska\n
John \optional{capable} sees.\n
John is innately capable of seeing.\n
John can see.
\end{example}
{\noindent}might be true about a human being named John, even though he
has been blind since birth, because the ability to see is
innately built into his nature as a human being. It is
theoretically possible that conditions might occur that would
enable John to see (a great medical discovery). On the other
hand,
\begin{example}
le cukta ka'e viska\n
The book \optional{capable} sees.\n
The book can see.
\end{example}
{\noindent}is not true in most epistemologies, since the ability to see is
not part of the innate nature of a book.
Consider once again the newly hatched ducks mentioned
earlier. They have the potential of swimming, but have not yet
demonstrated that potential. This may be expressed using
\q{nu'o}, the cmavo of CAhA for undemonstrated potential:
\begin{example}
ro cifydatka nu'o flulimna\n
all infant-ducks \optional{can but has not} are-float-swimmers.\n
All infant ducks have an undemonstrated potential\n
\T for swimming by floating.\n
Baby ducks can swim but haven't yet.
\end{example}
Contrariwise, if Frank is not blind from birth, then \q{pu'i}
is appropriate:
\begin{example}
la frank. pu'i viska\n
Frank \optional{can and has} sees.\n
Frank has demonstrated a potential for seeing.\n
Frank can see and has seen.
\end{example}
Note that the glosses given at the beginning of this section
for \q{ca'a}, \q{nu'o}, and \q{pu'i} incorporate \q{ca} into
their meaning, and are really correct for \q{ca ca'a}, ``ca
nu'o'', and \q{ca pu'i}. However, the CAhA cmavo are perfectly
meaningful with other tenses than the present:
\begin{example}
mi pu ca'a klama le zarci\n
I \optional{past} [actual] go-to the store.\n
I actually went to the store.
\end{example}
\begin{example}
la frank. pu nu'o klama le zdani\n
Frank \optional{past} [can but has not] goes-to the store.\n
Frank could have, but will not have, gone to the\n
\T store (at some understood moment in the\n
\T future).
\end{example}
As always in Lojban tenses, a missing CAhA can have an
indeterminate meaning, or the context can be enough to
disambiguate it. Saying
\begin{example}
ta jelca\n
That burns/is-burning/might-burn/will-burn.
\end{example}
{\noindent}with no CAhA specified can translate the two very different
English sentences \q{That is on fire} and ``That is
inflammable.'' The first demands immediate action (usually),
whereas the second merely demands caution. The two cases can be
disambiguated with:
\begin{example}
ta ca ca'a jelca\n
That \optional{present} [actual] burns.\n
That is on fire.
\end{example}
{\noindent}and
\begin{example}
ta ka'e jelca\n
That \optional{capable} burns.\n
That is capable of burning.\n
That is inflammable.
\end{example}
When no indication is given, as in the simple observative
\begin{example}
fagri\n
fire
\end{example}
{\noindent}the prudent Lojbanist will assume the meaning \q{Fire!}
\sect{Logical and non-logical connections between tenses}
Like many things in Lojban, tenses may be logically
connected; logical connection is explained in more detail in \chapref{14}. Some of the terminology in
this section will be clear only if you already understand
logical connectives.
The appropriate logical connectives belong to selma'o JA. A
logical connective between tenses can always be expanded to one
between sentences:
\begin{example}
mi pu je ba klama le zarci\n
I \optional{past} and [future] go-to the market.\n
I went and will go to the market.
\end{example}
{\noindent}means the same as:
\begin{example}
mi pu klama le zarci\n
\T .ije mi ba klama le zarci\n
I \optional{past} go-to the market.\n
\T And I [future] go-to the market.\n
I went to the market, and I will go to the market.
\end{example}
Tense connection and tense negation are combined in:
\begin{example}
mi punai je canai je ba\n
\T klama le zarci\n
I \optional{past} [not] and [present] [not] and [future]\n
\T go-to the market.\n
I haven't yet gone to the market, but I will in future.
\end{example}
\exref{10.20.3} is far more specific than
\begin{example}
mi ba klama le zarci\n
I \optional{future} go-to the market.
\end{example}
{\noindent}which only says that I will go, without claiming anything about
my past or present. \q{ba} does not imply \q{punai} or
\q{canai}; to compel that interpretation, either a logical
connection or a ZAhO is needed.
Tense negation can often be removed in favor of negation in
the logical connective itself. The following examples are
equivalent in meaning:
\begin{example}
mi mo'izu'anai je mo'iri'u cadzu\n
I \optional{motion} [left-not] and [motion] [right] walk.\n
I walk not leftward but rightward.
\end{example}
\begin{example}
mi mo'izu'a naje mo'iri'u cadzu\n
I \optional{motion} [left] not-and [motion] [right] walk.\n
I walk not leftward but rightward.
\end{example}
There are no forethought logical connections between tenses
allowed by the grammar, to keep tenses simpler. Nor is there
any way to override simple left-grouping of the connectives,
the Lojban default.
The non-logical connectives of selma'o JOI, BIhI, and GAhO
are also permitted between tenses. One application is to
specify intervals not by size, but by their end-points
(\q{bi'o} belongs to selma'o BIhI, and connects the end-points
of an ordered interval, like English \q{from ... to}):
\begin{example}
mi puza bi'o bazu vasxu\n
I \optional{past} [medium] from ... to [future] [long] breathe.\n
I breathe from a medium time ago till a long time\n
\T to come.
\end{example}
(It is to be hoped that I have a long life ahead of me.)
One additional use of non-logical connectives within tenses
is discussed in \sectref{10.21}. Other uses will
probably be identified in future.
\sect{Sub-events}
Another application of non-logical tense connection is to
talk about sub-events of events. Consider a six-shooter: a gun
which can fire six bullets in succession before reloading. If I
fire off the entire magazine twice, I can express the fact in
Lojban thus:
\begin{example}
mi reroi pi'u xaroi\n
\T cecla le seldanti\n
I \optional{twice} [cross-product] [six times]\n
\T shoot the projectile-launcher.\n
On two occasions, I fire the gun six times.
\end{example}
It would be confusing, though grammatical, to run the \q{reroi}
and the \q{xaroi} directly together. However, the non-logical
connective \q{pi'u} expresses a Cartesian product (also known
as a cross product) of two sets. In this case, there is a set
of two firings each of which is represented by a set of six
shots, for twelve shots in all (hence the name \q{product}: the
product of 2 and 6 is 12). Its use specifies very precisely
what occurs.
In fact, you can specify strings of interval properties and
event contours within a single tense without the use of a
logical or non-logical connective cmavo. This allows tenses of
the type:
\begin{example}
la djordj. ca'o co'a ciska\n
George \optional{continuitive} [initiative] writes.\n
George continues to start to write.
\end{example}
\begin{example}
mi reroi ca'o xaroi darxi le damri\n
I \optional{twice} [continuitive] [six times] hit the drum.\n
On two occasions, I continue to beat the drum six times.
\end{example}
\sect{Conversion of sumti tcita: JAI}
The following cmavo are discussed in this section:
jai JAI tense conversion
fai FA indefinite place
Conversion is the regular Lojban process of moving around the
places of a place structure. The cmavo of selma'o SE serve this
purpose, exchanging the first place with one of the others:
\begin{example}
mi cu klama le zarci\n
I go-to the market.
\end{example}
\begin{example}
le zarci cu se klama mi\n
The market is-gone-to by-me.
\end{example}
It is also possible to bring a place that is specified by a
sumti tcita (for the purposes of this chapter, a tense sumti
tcita) to the front, by using \q{jai} plus the tense as the
grammatical equivalent of SE:
\begin{example}
le ratcu cu citka le cirla vi le panka\n
The rat eats the cheese \optional{short distance} the park.\n
The rat eats the cheese in the park.
\end{example}
\begin{example}
le panka cu jai vi citka le cirla fai le ratcu\n
The park is-the-place-of eating the cheese by-the rat.\n
The park is where the rat eats the cheese.
\end{example}
In \exref{10.22.4}, the construction
JAI+tense converts the location sumti into the first place. The
previous first place has nowhere to go, since the location
sumti is not a numbered place; however, it can be inserted back
into the bridi with \q{fai}, the indefinite member of selma'o
FA.
(The other members of FA are used to mark the first, second,
etc. places of a bridi explicitly:
\begin{example}
fa mi cu klama fe le zarci
\end{example}
{\noindent}means the same as
\begin{example}
fe le zarci cu klama fa mi
\end{example}
{\noindent}as well as the simple
\begin{example}
mi cu klama le zarci
\end{example}
{\noindent}in which the place structure is determined by position.)
Like SE conversion, JAI+tense conversion is especially
useful in descriptions with LE selma'o:
\begin{example}
mi viska le jai vi citka be le cirla\n
I saw the place-of eating the cheese.
\end{example}
Here the eater of the cheese is elided, so no \q{fai}
appears.
Of course, temporal tenses are also usable with JAI:
\begin{example}
mi djuno fi le jai ca morsi\n
\T be fai la djan.\n
I know about the \optional{present} is-dead\n
\T of-the-one-called \q{John}\n
I know the time of John's death.\n
I know when John died.
\end{example}
\sect{Tenses versus modals}
Grammatically, every use of tenses seen so far is exactly
paralleled by some use of modals as explained in \chapref{9}. Modals and tenses alike can be
followed by sumti, can appear before the selbri, can be used in
pure and mixed connections, can participate in JAI conversions.
The parallelism is perfect. However, there is a deep difference
in the semantics of tense constructs and modal constructs,
grounded in historical differences between the two forms.
Originally, modals and tenses were utterly different things in
earlier versions of Loglan; only in Lojban have they become
grammatically interchangeable. And even now, differences in
semantics continue to be maintained.
The core distinction is that whereas the modal bridi
\begin{example}
mi nelci do mu'i le nu do nelci mi\n
I like you with-motivation the event-of you like me.\n
I like you because you like me.
\end{example}
{\noindent}places the \q{le nu} sumti in the $x_1$ place of the gismu
\q{mukti} (which underlies the modal \q{mu'i}), namely the
motivating event, the tensed bridi
\begin{example}
mi nelci do ba le nu do nelci mi\n
I like you after the event-of you like me.\n
I like you after you like me.
\end{example}
{\noindent}places the \q{le nu} sumti in the $x_2$ place of the gismu
\q{balvi} (which underlies the tense \q{ba}), namely the point
of reference for the future tense. Paraphrases of \exref{10.23.1} and \exref{10.23.2}, employing the brivla \q{mukti} and \q{balvi}
explicitly, would be:
\begin{example}
le nu do nelci mi cu mukti le nu mi nelci do\n
The event-of you like me motivates the event-of I like you\n
Your liking me is the motive for my liking you.
\end{example}
{\noindent}and
\begin{example}
le nu mi nelci do cu balvi le nu do nelci mi\n
The event-of I like you is after the event of you like me.\n
My liking you follows (in time) your liking me.
\end{example}
(Note that the paraphrase is not perfect due to the difference
in what is claimed; \exref{10.23.3} and \exref{10.23.4} claim only the causal and
temporal relationships between the events, not the existence of
the events themselves.)
As a result, the afterthought sentence-connective forms of\exref{10.23.1} and \exref{10.23.2} are, respectively:
\begin{example}
mi nelci do .imu'ibo do nelci mi\n
I like you. \optional{That is} Because you like me.
\end{example}
\begin{example}
do nelci mi .ibabo mi nelci do\n
You like me. Afterward, I like you.
\end{example}
In \exref{10.23.5}, the order of the two
bridi \q{mi nelci do} and \q{do nelci mi} is the same as in \exref{10.23.1}. In \exref{10.23.6}, however, the order is reversed: the origin point ``do
nelci mi'' physically appears before the future-time event ``mi
nelci do''. In both cases, the bridi characterizing the event
in the $x_2$ place appears before the bridi characterizing the
event in the $x_1$ place of \q{mukti} or \q{balvi}.
In forethought connections, however, the asymmetry between
modals and tenses is not found. The forethought equivalents of\exref{10.23.5} and \exref{10.23.6} are
\begin{example}
mu'igi do nelci mi gi mi nelci do\n
Because you like me, I like you.
\end{example}
{\noindent}and
\begin{example}
bagi do nelci mi gi mi nelci do\n
After you like me, I like you.
\end{example}
{\noindent}respectively.
The following modal sentence schemata (where X and Y
represent sentences) all have the same meaning:
\begin{description}
\item[] X .i BAI bo Y BAI gi Y gi X X BAI le nu Y
\end{description}
whereas the following tensed sentence schemata also have the
same meaning:
\begin{description}
\item[] X .i TENSE bo Y TENSE gi X gi Y Y TENSE le nu X
\end{description}
neglecting the question of what is claimed. In the modal
sentence schemata, the modal tag is always followed by Y, the
sentence representing the event in the $x_1$ place of the gismu
that underlies the BAI. In the tensed sentences, no such simple
rule exists.
\sect{Tense questions: \q{cu'e}
}
The following cmavo is discussed in this section:
cu'e CUhE tense question
There are two main ways to ask questions about tense. The main
English tense question words are \q{When?} and \q{Where?}.
These may be paraphrased respectively as \q{At what time?} and
\q{At what place?} In these forms, their Lojban equivalents
simply involve a tense plus \q{ma}, the Lojban sumti question:
\begin{example}
do klama le zdani ca ma\n
you go-to the house \optional{present} [what sumti?].\n
You go to the house at what time?\n
When do you go to the house?
\end{example}
\begin{example}
le verba vi ma pu\n
\T cadzu le bisli\n
The child \optional{short space} [what sumti?] [past]\n
\T walks-on the ice.\n
The child at/near what place walked on the ice?\n
Where did the child walk on the ice?
\end{example}
There is also a non-specific tense and modal question,
\q{cu'e}, belonging to selma'o CUhE. This can be used wherever
a tense or modal construct can be used.
\begin{example}
le nanmu cu'e batci le gerku\n
The man \optional{what tense?} bites the dog.\n
When/Where/How does the man bite the dog?
\end{example}
Possible answers to \exref{10.24.3} might be:
\begin{example}
va\n
\optional{medium space}.\n
Some ways from here.
\end{example}
\begin{example}
puzu\n
\optional{past} [long time].\n
A long time ago.
\end{example}
\begin{example}
vi le lunra\n
\optional{short space} The moon.\n
On the moon.
\end{example}
\begin{example}
pu'o\n
\optional{inchoative}\n
He hasn't yet done so.
\end{example}
{\noindent}or even the modal reply (from selma'o BAI; see \chapref{9}):
\begin{example}
bai la djan.\n
Under John's compulsion.
\end{example}
The only way to combine \q{cu'e} with other tense cmavo is
through logical connection, which makes a question that
pre-specifies some information:
\begin{example}
do puzi je cu'e sombo le gurni\n
You \optional{past} [short] and [when?] sow the grain?\n
You sowed the grain a little while ago;\n
\T when else do you sow it?
\end{example}
Additionally, the logical connective itself can be replaced
by a question word:
\begin{example}
la .artr. pu je'i ba nolraitru\n
Arthur \optional{past} [which?] [future] is-a-king\n
Was Arthur a king or will he be?
\end{example}
Answers to \exref{10.24.10} would be
logical connectives such as \q{je}, meaning \q{both}, \q{naje}
meaning \q{the latter}, or \q{jenai} meaning ``the
former''.
\sect{Explicit magnitudes}
It is a limitation of the VA and ZI system of specifying
magnitudes that they can only prescribe vague magnitudes:
small, medium, or large. In order to express both an origin
point and an exact distance, the Lojban construction called a
\q{termset} is employed. (Termsets are explained further in \chapref{14} and \chapref{16}.) It is grammatical for a
termset to be placed after a tense or modal tag rather than a
sumti, which allows both the origin of the imaginary journey
and its distance to be specified. Here is an example:
\begin{example}
la frank. sanli zu'a nu'i la djordj.\n
\T lu'a lo mitre\n
\T be li mu \optional{nu'u}\n
Frank stands [left] [start termset] George\n
\T [quantity] a thing-measuring-in-meters\n
\T the-number 5 [end termset].\n
Frank is standing five meters to the left of George.
\end{example}
Here the termset extends from the \q{nu'i} to the implicit
\q{nu'u} at the end of the sentence, and includes the terms
\q{la djordj.}, which is the unmarked origin point, and the
tagged sumti \q{lo mitre be li mu}, which the cmavo \q{la'u}
(of selma'o BAI, and meaning \q{with quantity}; see \chapref{9}) marks as a quantity. Both
terms are governed by the tag \q{zu'a}
It is not necessary to have both an origin point and an
explicit magnitude: a termset may have only a single term in
it. A less precise version of \exref{10.25.1}
is:
\begin{example}
la frank. sanli zu'a nu'i lu'a\n
\T lo mitre be li mu\n
Frank stands \optional{left} [termset] [quantity]\n
\T a thing-measuring-in-meters the-number 5.\n
Frank stands five meters to the left.
\end{example}
\sect{Finally (an exercise for the much-tried reader)}
\begin{example}
a'o do pu seju ba roroi ca'o fe'e su'oroi jimpe\n
\T fi le lojbo temci selsku ciste
\end{example}
\sect{Summary of tense selma'o}
\begin{description}
\item[PU] temporal direction pu = past, ca = present, ba = future ZI temporal distance zi = short, za = medium, zu = long ZEhA temporal interval ze'i = short, ze'a = medium, ze'u = long, ze'e = infinite ROI objective quantified tense flag noroi = never, paroi = once, ..., roroi = always, etc. TAhE subjective quantified tense di'i = regularly, na'o = typically, ru'i = continuously, ta'e = habitually ZAhO event contours see \sectref{10.10}\item[FAhA] spatial direction see \sectref{10.27} VA spatial distance vi = short, va = medium, vu = long VEhA spatial interval ve'i = short, ve'a = medium, ve'u = long, ve'e = infinite VIhA spatial dimensionality vi'i = line, vi'a = plane, vi'u = space, vi'e = space-time FEhE spatial interval modifier flag fe'enoroi = nowhere, fe'eroroi = everywhere, fe'eba'o = beyond, etc. MOhI spatial movement flag mo'i = motion; see \sectref{10.27}
\item[KI] set or reset sticky tense tense+\q{ki} = set, \q{ki} alone = reset CUhE tense question, reference point cu'e = asks for a tense or aspect nau = use speaker's reference point JAI tense conversion jaica = the time of, jaivi = the place of, etc.
\end{description}
<h3>
28. List of spatial directions and direction-like
relations</h3>
The following list of FAhA cmavo gives rough English glosses
for the cmavo, first when used without \q{mo'i} to express a
direction, and then when used with \q{mo'i} to express movement
in the direction. When possible, the gismu from which the cmavo
is derived is also listed.
cmavo gismu without mo'i with mo'i
----- ----- ------------ ---------
ca'u crane in front (of) forward
ti'a trixe behind backward
zu'a zunle on the left (of) leftward
ri'u pritu on the right (of) rightward
ga'u gapru above upward(ly)
ni'a cnita below downward(ly)
ne'i nenri within into
ru'u sruri surrounding orbiting
pa'o pagre transfixing passing through
ne'a next to moving while next to
te'e bordering moving along the border (of)
re'o adjacent (to) along
fa'a farna towards arriving at
to'o away from departing from
zo'i inward (from) approaching
ze'o outward (from) receding from
zo'a tangential (to) passing (by)
bu'u coincident (with) moving to coincide with
be'a berti north (of) northward(ly)
ne'u snanu south (of) southward(ly)
du'a stuna east (of) eastward(ly)
vu'a west (of) westward(ly)
Special note on \q{fa'a}, \q{to'o}, \q{zo'i}, and \q{ze'o}:
\q{zo'i} and \q{ze'o} refer to direction towards or away
from the speaker's location, or whatever the origin is.
\q{fa'a} and \q{to'o} refer to direction towards or away
from some other point.
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