What's the furthest back we can prove human existence? Is there good reason to believe it goes further then this point?
The furthest back we can currently prove human existence is around 300,000 years ago, based on fossil evidence of early Homo sapiens found in Morocco. However, there is ongoing research and debate about when and how humans first appeared on Earth, and some evidence suggests that human evolution may extend further back in time.

For example, there are fossil remains of hominins, the group of primates that includes modern humans and their extinct ancestors, dating back as far as 7 million years ago. These early hominins were not fully bipedal or human-like, but they represent important stages in the evolution of our species.

Additionally, genetic studies have provided some insights into the evolutionary history of humans. For example, studies of mitochondrial DNA suggest that humans may have diverged from chimpanzees and other great apes around 7-10 million years ago, although there is still much debate and uncertainty about the precise timing and mechanisms of human evolution.

Overall, while the furthest back we can currently prove human existence is around 300,000 years ago, there is ongoing research and evidence that suggests our evolutionary history may extend much further back in time. As our understanding of human evolution continues to evolve, we may discover new evidence and insights that shed light on the origins and development of our species.
What is the longest amount of time we can currently prove human existence using fossil evidence? When did the first early hominins appear on Earth, according to fossil evidence?
The longest amount of time we can currently prove human existence using fossil evidence is around 300,000 years ago, with the discovery of early Homo sapiens fossils in Morocco. However, if we consider the broader category of hominins, which includes modern humans and their extinct ancestors, the timeline extends much further back.

According to fossil evidence, the first early hominins appeared on Earth around 7 million years ago. These early hominins, such as Sahelanthropus tchadensis, were not fully human-like or bipedal, but they represent crucial stages in the evolution of our species. As new evidence and discoveries are made, our understanding of human evolution and the timeline of our species' development will continue to evolve.