<s>[INST] What's the furthest back we can prove human existence? Is there good reason to believe it goes further then this point? [/INST] Human is an ever-evolving species. If we starts from _Homo sapiens_ the species, there are traces of human in Africa since 300,000 years ago. For _Homo_ genus, earliest fossil record discovered so far is dated around 2.8 million years ago.

The above dates are based on fossil records. It is completely possible for new fossil emerges with an earlier date. It is also possible that carbon dating, technique used to determine fossil age, may not be accurate. For example if there are more carbon-14 than we thought there would be in the past, we would underestimate the age of existing fossils, pushing human history further back.</s>\ <s>[INST] How reliable is carbon dating exactly? [/INST] There is no exact answer to how reliable carbon dating is. It depends on many factors, such as the quality of the sample, the calibration of the equipment, and the assumptions made about the past. Generally speaking, carbon dating can be accurate up to about 50,000 years ago, but beyond that it becomes less reliable. The margin of error can range from a few years to several thousand years, depending on the situation.</s>