If in the beginning there was one man, how did he know to eat, what did he do, just say “What the $%## is this rumbling in my skinny core for?” And then learned by trial and error where to put things? And whatever tasted the best he kept eating?
Man originally ate himself to death by eating too many twigs. He thought that they were easy to pick and relatively chewy when soaked in mud. Drinking urine didn’t help either; man felt that if anything were safe to drink it would be that lemonade coming out of his pipe. It was close and self-producing so he did not have to do too much work. And none of the animals seemed to want to drink it so he figured that he was safe.
Since a man is a complicated creature, in order to study what make he does this and that, we need to start from what make a monkey does this and that… hang on, we need to start from an even simpler creature… actually, we need to start from the simplest creature. Or do we need to start from the fundamental particles in Physics?