According to the Argument from Religious Experience, people have religious experiences experiences of the supernatural, like heaven or angels or even a god. Because we believe other experiential claims people make like that they went to the store or own a car then we should believe these claims as well. It is also argued that when skeptics apply higher standards for claims based on religious experiences than they do for claims based on other experiences, they exhibiting a prejudice against religious claims. This prevents them from understanding and ultimately believing.
William James offers a classic version of this argument in his influential Varieties of Religious Experience. He argues that all normal persons have religious experience and, since experience is the final arbiter of truth, then God as the object of religious experiences must be accepted as factually true. James further observes that the religious experiences in question tend to have a profound effect on the lives of people and even whole societies, implying that such effects cannot reasonably be attributed to hallucinations. Instead, it is much more reasonable to believe that a real God is responsible for religious experiences than to attribute the profound effects of those experiences to a mere imaginary being.
The first problem is in James assertion that all normal people have religious experiences. It is uncertain what exactly he means by this, but it is a much easier assertion to make than to support. If he means experiences of the supernatural gods, angels, etc. then he is wrong. If he means something much more vague, like that everyone has experienced awe when contemplating the universe, then he might be right but he isnt supporting his claim.
The second problem is in the variety of religious experiences: if there is just one God, why is there such wide variety in the reports of religious experiences? Indeed, they are mutually incompatible. They cant all be true, so at least some must be false. How do we differentiate? What reasons can the religious believer give to accept her reports over the reports made by others?
There are no independent criteria we can use to separate the genuine experiences from false or flawed experiences not only in the reports of others, but in ourselves. The only criteria which might exist rely upon the validity of some religious system. For example, some argue that a religious experience which does not agree with the Bible is flawed or false but since this ultimately assumes the truth of what is supposed to be proven, such criteria are unacceptable.
The third problem is in the idea that the profound effects these experiences have is any indicator of the truth. We can grant that people have some sort of experience and we can certainly grant that the experiences have a profound effect; but does this mean we must accept the reported content of these experiences that they were of a supernatural nature? No.
Real experiences that have a profound impact on a person can have completely natural sources without any divine connections. Mystical experiences can be reproduced in anyone, both with chemical substances and mechanical equipment. With this being the case, what reason is there to think that other reports actually stem from a supernatural, rather than a natural, cause? If at least some of the alleged religious experiences are wholly natural, how do we separate them from the truly supernatural ones? Even if an experience changes the course of a society, that does not testify that the experiences had supernatural origins. At most, it might point to the persuasiveness of the believers or the appeal of the claims.
Some, like Richard Swineburne, argue that the degree to which it seems to a person that something has happened should translate into the probability that something has happened. It is true that when people say that it seems to them that a chair is in a room that, therefore, we tend to accept that a chair is in the room. It is not true, however, that every time someone genuinely and seriously believes something, we also accept that whatever they believe is probably true.
We only accept this when it comes to more mundane things which we all have experiences of. When someone says that it seems to them very strongly that an elf is in the room, we do not accept that there is probably an elf in the room, do we? Even if we accept Swineburnes argument, we must also accept that when people try to have an experience of a god and fail, that this is good reason to believe that a god probably does not exist. After all, it would be prejudiced to dismiss the experiences of nonbelievers but privilege the experiences of those who already believe.