The psychedelic researcher and philosopher Terence McKenna proposed the “stoned ape” hypothesis — that psychedelic plant use was a driver of the cognitive evolution that produced modern human intelligence.

This specific hypothesis is not generally accepted in the scientific mainstream, but the broader question of whether and how psychoactive plant use has shaped human cognitive and cultural evolution is a legitimate area of inquiry.

What does the antiquity of drug use mean for how we think about it?

If humans have been using psychoactive plants for at least 25,000 years — and probably longer — does that inform how we think about the social and legal regulation of drug use today?

The argument that drug use is a modern pathology — a consequence of social breakdown, of modernity’s discontents — is harder to sustain against evidence that it predates civilization by orders of magnitude.