All quotes from Terence McKenna’s

The right strategy with these shamanic hallucinogens is this effort to see them as intervention into ordinary brain chemistry.

It’s absolutely central to an intelligent species to have a symbiotic relationship with the matrix of life on its planet. Otherwise, the intelligent species will quickly elaborate a set of lethal cultural adaptations which will have negative feedback into the planetary life system—precisely the situation in which we find ourselves. Intelligence on the surface of a planet must be mediated by a symbiotic relationship with the rest of the living world.