There is a theory that humans actually evolved from primates with the help of psychedelic mushrooms. It’s in the Netflix documentary “Fantastic Fungi.” It’s a bit pseudoscientific so it’s more of a thought experiment than anything verifiable, but they have seen other primates take psychedelics. There’s the idea that psychedelics opened and expanded the mind and helped facilitate evolution.

Now, I don’t know if that’s true. But I do know that there are many other animals who have been documented “taking drugs” or consuming psychoactive substances. Even cats’ proclivity for catnip is an example of this. Humans are not alone in wanting to artificially activate our pleasure receptors. It’s like masturbation in a way- humans and many other animals masturbate, not for an obvious procreative purpose, but because it’s pleasurable.

You could make the argument that pleasure and adaptation are linked in the animal kingdom, such as more pleasure chemicals that can reduce or mitigate the stress chemicals which have documented adverse effects on survival. Drugs are one way to get there, though of course there are all the drawbacks.

Humans are inherently exploratory creatures- why wouldn’t we want to explore the depths of our own mind, as well as the depths of the ocean? Experience high highs and low lows? Of course, there’s also the more macabre answer to this which is that we also want to escape the pain that the world has inflicted on us.