In the case of certain kinds of transformational experiences—such as meeting the love of your life—you have the realization that this is something you really needed for flourishing, but didn’t know it. Further, in many cases of these kinds of experiences, part of that realization is not just that you need the subjective experience for flourishing, but that what you need for reality the flourishing. For instance, if it turns out that your experience of meeting the love of your life was a hallucination, it would be a part of your realization not just that you need an experience of meeting the love of your life, but that you need the reality.
Now I think this kind of realization is a part of the life of many theists in connection with the experience of a relationship with God: they come to realize that they have always needed both this experience and the reality of it. But then the theist has this argument:
What is needed for the flourishing of a human being is in principle possible.
A relationship with God is in principle possible only if God exists.
A relationship with God is needed for my flourishing.
So, God exists.
An interesting thing about this argument is that for a number of people, the full realization of the truth of premise (3) only comes about once they believe in God. The argument thus has a circularity of sorts: it works best for those who already believe the conclusion. This is an innocent circularity: the relationship with God, of which belief in God is a part, makes available significant evidence for that belief.
This is a bit like Kierkegaard’s “argumentum Spiritus Sancti” which is only available to those who believe. It sounds paradoxical, but I do not think it is actually all that paradoxical. Imagine you have a friend who is accused of some crime, but refuses to show you evidence of their innocence unless you believe in their innocence first. Then, your belief is needed for you to have the evidence, but the evidence can be perfectly genuine and unparadoxical.
