[insane_dreamer]

Ancient cultures relied on observation-based trial-and-error knowledge passed down from generation to generation, mostly involving people dying. They didn't have to understand the causes in order to be correct about the effect. E.g., if you eat raw meat that's been sitting there a while, you get sick and might die. How do we know? Because X and Y people died after eating it. But if you cook it, you don't get sick and don't die. How do we know, because A and B people cooked it and didn't die. Thus -> cook meat. Why? Who knows what unscientific reasons they would give (likely superstitious ones). But "discoveries" of this sort were passed down, in the same way that they discovered which mushrooms not to eat (by people dying when they ate them).

Same applied to which local sources of water were safe to drink (i.e., people didn't die when they drank from there), and whether fermented drink (i.e., beer) was safer than water.

[hnlmorg]

A lot of what our evolved tastes are today actually comes from biological repulsion for stuff that isn’t safe for consumption.

This is why smell was so important.

Unfortunately smell isn’t an accurate gauge for whether a source is safe or not.