Following up on my previous post about John Dewey's marvelous little book, "A Common Faith," here's some of what Dewey has to say about mystical experiences. I've boldfaced some passages that particularly appeal to me.
Dewey's main point, which I totally agree with, is that by themselves, mystical experiences prove nothing about God or the supernatural.
The possible causes of those experiences must be carefully studied before any conclusions can be drawn about them, especially given the wide variety of mystical experiences, many or most of which have no commonality.
It is more to the point, however, to consider the region that is claimed by religionists as a special reserve. It is mystical experience. The difference, however, between mystic experience and the theory about it that is offered to us must be noted.
The experience is a fact to be inquired into. The theory, like any theory, is an interpretation of that fact.
The idea that by its very nature the experience is a veridical [truthful] realization of the direct presence of God does not rest so much upon examination of the facts as it does upon importing into their interpretation a conception that is formed outside them.
In its dependence upon a prior conception of the supernatural, which is the thing to be proved, it begs the question.
History exhibits many types of mystic experience, and each of these types is contemporaneously explained by the concepts that prevail in the culture and the circle in which the phenomena occur.
There are mystic crises that arise, as among some North American Indian tribes, induced by fasting. They are accompanied by trances and semi-hysteria. Their purpose is to gain some special power, such perhaps as locating a person who is lost or finding objects that have been secreted.
There is the mysticism of Hindoo practice now enjoying some vogue in Western countries. There is the mystic ecstasy of Neoplatonism with its complete abrogation of the self and absorption into an impersonal whole of Being.
There is the mysticism of intense aesthetic experience independent of any theological or metaphysical interpretation. There is the heretical mysticism of William Blake. There is the mysticism of sudden unreasoning fear in which the very foundations seem shaken beneath one -- to mention but a few of the types that may be found.
What common element is there between, say, the Neoplatonic conception of a super-divine Being wholly apart from human needs and conditions and the medieval theory of an immediate union that is fostered through attention to the sacraments or through concentration upon the heart of Jesus?
...There is no reason for denying the existence of experiences that are called mystical. On the contrary, there is every reason to suppose that, in some degree of intensity, they occur so frequently that they may be regarded as normal manifestations that take place at certain rhythmic points in the movement of experience.
The assumption that denial of a particular interpretation of their objective content proves that those who make the denial do not have the experience in question, so that if they had it they would be equally persuaded of its objective source in the presence of God, has no foundation in fact.
As with every empirical phenomenon, the occurrence of the state called mystical is simply an occasion for inquiry into its mode of causation. There is no more reason for converting the experience itself into an immediate knowledge of its cause than in the case of an experience of lightning or any other natural occurrence.