The God of Anselm is understood as "that than which nothing greater can be conceived." From this definition, God can be presumed to be omnipotent, omniscient, omnipresent, perfectly free, uncaused, eternal, morally perfect, etc. God is fashioned as an infinite being, i.e. one who's abilities have no non-logical limitations. This definition, however, leaves us in an awkward epistemological position, as it ostensibly renders all potential evidence for such a being inherently ambiguous.
To speak specifically, any miracle, feat, or theophany wrought by an infinite being could—in principle—have also been performed by a finite being. That is to say, there seems to be an ineradicable ambiguity in any manifestation of an infinite being's power, precisely for the reason that the very same action could have been performed by a being that was not infinite. How might we finite beings ever know, definitively, which being we are actually dealing with?
How could any being, even God, possibly demonstrate His omnipotence? Omniscience? Moral perfection? How could we ever tell the difference between God and a being that is merely “God-like”? It would appear that these infinite attributes are—by their very nature—incapable of actual demonstration, and are thus intrinsically unverifiable. I am at a loss to explain how apologists set out in earnest to adumbrate the case for an infinite God when unambiguous evidence for such a being appears to be in principle unattainable.
Consider an analogous situation: Imagine that you are sitting in a room with nothing in it apart from a chain which enters from one side of the room and exits through the other side. From your vantage point you cannot see the outside world, but you can see that the chain clearly does not begin or end within the confines of the room. We are then asked, “Is this chain infinite?” How can our answer be anything other than a guess? What evidence or argument could possibly be adduced that would settle the matter definitively? It would appear that we are in no position to know which type of object we're dealing with, and therefore cannot verify that the chain is in fact infinite, even if it actually is. This epistemic hurdle seems to parallel any and all attempts to marshal evidence for an infinite God based on human experience (no matter how ineffable). Even if we were to experience the unmistakable presence of a powerful, immaterial, and personal being, we seem nevertheless to be in no position to say whether or not this being is essentially infinite.
How can we have unambiguous evidence for an infinite being if we cannot even verify that the being is infinite? How do we know it's not all in our heads? Perhaps to professional philosophers this not as big a problem as it appears to a layman like myself, but every time I try to think of ways to empirically justify theism, I fail to progress beyond this notion that any evidence for an infinite being is simultaneously evidence for an finite being. Am I completely off-base here?