What is the Hard Problem of consciousness and what makes it so hard?
The Hard Problem of consciousness is a philosophical problem related to the nature of subjective experience, which is also called phenomenal consciousness. It is called hard because it is difficult to explain why and how subjective experiences arise from the physical processes of the brain.

The Hard Problem of consciousness is different from the easy problems of consciousness, which are concerned with the neural and cognitive mechanisms that underlie various mental processes, such as perception, memory, attention, and so on. The easy problems are considered easy because they can, in principle, be solved by empirical research and scientific inquiry.

In contrast, the Hard Problem asks why conscious experience exists at all, and why it has its specific qualitative character. For example, why does seeing the color red feel like anything at all, rather than just a bunch of physical processes in the brain? Why is the experience of pain so different from the experience of pleasure? And how can we explain the unity and coherence of conscious experience, which seems to be more than just a sum of individual sensory inputs?

The Hard Problem is considered hard because it seems to resist any reductionist or materialist explanation. In other words, it is difficult to see how subjective experience can be explained solely in terms of the physical processes of the brain or any other physical system. This is sometimes called the explanatory gap between the subjective and objective domains of reality.

Various theories have been proposed to try to solve the Hard Problem, such as panpsychism, idealism, dualism, and others, but none of them have yet gained wide acceptance in the scientific or philosophical communities.