What do I say to the “I’m Spiritual but Not Religious” Claim?

You could start by asking, “Have you ever received an answer to a question that you weren’t satisfied with, and pursued further information?” Or “Have you ever been frustrated when someone failed to love you in the way that you desired?” Without doubt, the person will answer yes to both questions.

Point out that these experiences indicate that they are religious by nature. How so? The recognition of the limitation of truth and love, and the frustration experienced when such a limitation is recognized, indicates that we desire truth and love. And inasmuch as we desire truth and love, we desire God, since God is the perfection of truth and love. And to pursue God, even in implicit ways, is to be a religious being.

Now, often what people mean when they say “I’m spiritual but not religious” is that they believe in a higher power, or even God, but they don’t think they have to belong to any particular religion. So, the line of response would have to involve a defense of Jesus’ divinity, a historical account of the establishment of his Church, and a proof that the Catholic Church is that historical church. For if Jesus did establish the Catholic Church, and we knew about it, we would be morally obliged to enter into it. It would matter to be Catholic.

For more ways to respond to this sort of claim, see Jimmy Akin’s responses here.