There are certain persistent problems with visionary experiences. Take an example. I am sitting here at the computer. My wife can see the computer, so there is a public character to the perception. If I, however, can see the Virgin Mary standing in the corner, but she cannot, then we have some explaining to do. The following possibilities occur:either I have special powers that she does not; or we both have the same powers, but only I have been chosen to receive the vision; or I am hallucinating, due to temporary or permanent impairment of my sanity [she is convinced of the latter!] No one can prove that visionaries in these cases have not experienced something, but the status of what they have seen is difficult to ascertain.
The problem is the relationship between image and reality. Many people do not realize that we do not see the world, as it is, but as it is interpreted by the mind. Even when we are observing realities in the physical world we do not perceive them as they are. We perceive in an interpreted way. The reason is that what strikes our eyes is merely light, which is converted into electrical impulses by the brain. We are not born with a developed perception. Perception must be learned by the child. Kant was aware that we see not the noumenon, the thing as it is, but only the phenomenon, the thing as it appears to us.
Now a thinker called Tennant argued that our brains have evolved to get our view of the world right. Otherwise our species would be unable to cope and would have become extinct. But this applies to the common sense, everyday world, which we can agree we see aright. But what of the world revealed by religious visions? It is not as easy to handle, because the common sense on which we rely does not apply here. The phenomenon is essentially mysterious, so we must be more chary.
So what is happening when we have a religious vision? If it is a genuine vision, we are in some kind of non-sensory contact with a religious reality.As the religious reality is spiritual it has no visible form, but our minds impose a form upon it, for this is the only way in which we can handle the phenomenon. Yet the form imposed may not be visual. Richard Rolle, one of the fourteenth century English mystics, enjoyed religious experiences in the form of exquisite music.