No verifiable evidence is the Christian position

[Esquilax]

What about optical illusions? Or how about this: does everything exist exactly as you see it? The sun looks perfectly spherical--are we justified in believing it is indeed a sphere? Can you confidently call a rock a rock without examining it to the last atom? Where do you draw the line between a rock and a boulder? Is that line verifiable... or do you the categories come from your head?

Of course there's a level of subjectivity involved, this isn't an exact science or anything. Some might look at a rock and call it a pebble, or a stone, or any other number of descriptors; what matters is, we're both seeing the same object, and our other senses interact with it in ways that correspond with our initial sight; we can touch it, taste it, etc etc.

No matter the fine details; sense evidence is good for verifying existential claims, even if additional investigation is required to pick out everything about the thing in question. As for optical illusions, you might be seeing something that isn't there, but it won't have a physical presence that corresponds to any of your other senses, which should be your first hint that something is up.