I'm a materialist who believes in Scientism-- especially when I can reduce other talking monkeys into objects of financial exploitation-- because​ that's what Darwinism teaches; I don't like rabbit holes but love pigpens, wherein I can eat all the prime rib I so richly deserve, while I drown myself in good ole whiskey and beer!
Anyway, it's clear that human religiosity was greatly affected by entheogens; if not stemming directly from them. 
Metaphysics is a branch of philosophy which deals with the core nature of things (objects)...Anyone who claims that we know the definitive answer to this question in 2017 is practicing​ dishonesty....