A reader writes:
It seems to me that the debate between spiritualist and scientific interpretations of the psilocybin experience depends on a false alternative. It's true that a scientific perspective rules out witnessing supernatural facts. But that's not the same as ruling out witnessing spiritual facts, at least not in the sense that most people mean by the word "spiritual".
It is entirely compatible with what science has revealed about the world that human individuals bear a profound kinship to other parts of the universe, a kinship that ought to have tremendous value. The common misconception that science - unlike the Medieval world-view it replaced - implies our alienation from the world - our being strangers in a valueless world indifferent to our fates - ignores what science has shown. Darwin's theory, for example, shows the profound connections that all creatures, including human beings, bear to each other. We learn about our own bodies by studying the genes of house flies!
If contemporary science is right, we are parts of the universe in a more profound way than most religious traditions have ever suspected. Furthermore, we play a very special role in the universe: we (as well as other sapient species, if there are any) are the universe becoming conscious of itself - matter coming to the realization of its own existence, both the fact of it and its nature.
The realization of our connectedness with and kinship to everything is a deeply spiritual one. If anything should be valued (and valuing is a non-negotiable part of human experience), then this reflexive awareness that, through our existence, the universe has of its own beauty, power, and complexity, should be. The valuing of this profound fact is as spiritual an experience as I can think of.
Of course, it's not the same kind of spirituality as many mainstream religions offer. It's true that it eliminates the notion of a personal God, separate from the universe, with an interest in the fates of each and everyone of us. But the alternative it offers is still profoundly spiritual. As one of your other commentators noted, the idea that our existence is fleeting makes each moment precious and irreplaceable. Each human individual is a unique manifestation of the universe's growing awareness of itself. I certainly find this thought awesomely spiritual. And psilocybin experiences give individuals the direct experience of such facts. One looks at a tree, and one feels at home with it, part of the same enterprise, in some sense.
This is exactly what science teaches. But psilocybin enables one to experience such facts directly - thus its spiritual value. It is one thing to theoretically appreciate a natural phenomenon - say a supernova - and another to experience it directly through instruments, like telescopes. I think psilocybin is an instrument that enables us to experience directly facts that science has long appreciated theoretically: that we are profoundly at home in this universe, and have a special role in it - that of constituting its growing awareness of itself.
This may be a kind of Spinozistic pantheism enhanced with a Hegelian conceptualization of the human role in it. So it's not the kind of spirituality preached by most religions. But it is a kind of spirituality consistent with science, that makes clear why the human experience of and connection to nature is of paramount value. It is this spiritual insight that the psilocybin experience can reveal in a uniquely direct way.
But what if the universe being conscious of itself is a workable definition of God? In which case, we are indeed made in the image of God but our consciousness is limited by our humanity, by the "fall". I find far less conflict between these spiritual experiences and the religions that feel threatened by them than others do.