To be in a Passion you Good may do,
But no Good if a Passion is in you.
In a fascinating article on NPR, Barbara Bradley Hagerty considers evidence that neuroscientists are closing in on a physiological basis for spiritual experience. As always it is immensely complicated, but it seems to involve serotonin (which is influenced by LSD and other hallucinogenic drugs) and the temporal lobe (affected by some types of epilepsy). But in a sense the neurological details are irrelevant as compared to the ultimate question of whether spiritual experience is subjective or objective, whether it says more about us or about the world outside.
This relates to the primeval roots of philosophy. As I perceive my coffee cup, how can I be sure that it actually exists outside of me in the universe, rather than just as a physiological pattern in my brain? Sure, I can see it, touch it, drink coffee out of it, or break it, but all of these experiences are mediated by my brain--there is no way to know the coffee cup directly. This is related to the problem of philosophical (not political) idealism, or the dorm-room question, "How do I know I am not actually dreaming when I am not awake?"
Arguably and practically we settle this as a matter of consensus. We are irreducibly social beings, and so long as those around me, for instance, agree that there is a coffee cup on the table, I have no legitimate reason to question it. To be sure, these other people could also be mere phantoms of my brain (back to "life as a dream"), but so long as these people exist and behave according to consensually decided physical and psychological laws, this isn't really a problem.
As Hagerty's article mentions, it is agreed by most who actually reflect on the matter that all kinds of experiences near and dear to us exist as brain events. So, what about an experience such as love? Does the fact that love is biochemical in the beholding subject detract in any way from its attachment to the beheld object? Not at all. Love is as precious in the brain as it would be if it were off floating in the ether somewhere (much more so in fact). What matters is that the "love reaction" in the brain be reliably and meaningfully correlated with another person out in the world. If this reaction is set off by the sight of virtually any potentially available partner (the Don Giovanni phenomenon), then this is surely a problem, but it is psychological and relational, not biochemical or philosophical.
Love is an evaluative experience, and one that, significantly, we need not seek consensus for, so its subjectivity is not a difficulty. I do not need my fellows to confirm my experience by falling in love themselves with my beloved (indeed, this is the last thing I want). As such it is totally different from the matter-of-factly epistemological task of recognizing objective states of affairs in the world. Ethical and aesthetic phenomena partake of both aspects--consensually subjective attitudes are sought on the basis of consensually objective artifacts or moral outcomes.
The philosophical problem of most religious phenomena is that they combine both of these aspects, epistemological and evaluative, in a more questionable fashion. They postulate often quite specific states of affairs in the universe (e. g. it was created in such and such way, God has such and such attributes, did such and such) and also enjoin particular attitudes and evaluations that ought to follow from this (e. g. you must embrace this deity, you must avoid such and such actions). The problem, of course, is that while I can in practice get essentially 100% of my fellows to agree that there is a coffee cup on the table, I cannot arrive at anywhere near that degree of unanimity when it comes to cosmic states of affairs, at least beyond artificially organized subgroups.
This embarrassing situation prompts many liberal apologists to minimize theological speculations and focus on the emotional heart of spiritual experience. It is interesting that after one strips away theology and church doctrine, what is left is what Aldous Huxley called "The Perennial Philosophy," which is also what often accompanies hallucinogenic drugs and temporal lobe phenomena. That is, one arrives at a generally transcendent sense of plenitude, of the unity of beings and the universe, of a white light, and of ecstatic peace and acceptance. In other words, one arrives at the primal sense of love, but confusingly, without a clear love object.
Perhaps the history of conventional religion is the communal attempt to soothe this cognitive dissonance, to find--to create if necessary--a cosmic object worthy of this cosmic feeling. Needless to say, the project has had mixed results, but as for many that feeling (or perhaps more accurately, the need to have what Freud called the "oceanic" feeling, which I too have had) won't go away, the effort proceeds.
So the heart of religion, at its most barebones and austere, may be love of the universe. But if the universe is in fact the love object, then the project of knowing and specifying the beloved is science, and the act of praising the universe is poetry (by which I mean all the arts). Is there anything else?