“I believe that there are some things we can’t understand.”
Fine, but what does that mean? It’s likely people can mean more than one thing by saying that. What I am sure of is that it can be misused.
It’s probably the same thing to say “things that we can’t know.” The context in which I have seen this used has usually (if not always) been one in which someone believes in something that can’t really be proven or at least explained scientifically. However, this is no argument, not really in support of anything.
Presumably someone may mean this by it: I believe in a phenomenon that cannot be scientifically proven, or that can even be disproven by science. Because it’s a matter that we cannot understand, what science says about it is irrelevant.
I’ve even seen this: Don’t you realise that we can’t explain everything? It’s intellectually arrogant of you to presume to say that I am wrong, since we can’t understand this anyway.
Of course, there’s also this one: I admit that this is just a matter of faith, but I believe anyway, and I also believe reason and science have nothing to say about this.
The last one is sort of acceptable. Sure, go ahead and believe for no reason, since you even admit it. But as for the other two…
Yes, there could always be things we can’t understand. How would I know? How could anyone? But then, how on Earth do you know this thing? If we can’t understand these things, how come you understand them so well? At least well enough, that is, that you know more about them than methods of science or suchlike can reveal. If our best, most objective methods of inquiry cannot reveal their nature to us, why would your more subjective impressions be more correct? “We cannot know” most certainly does not mean “Any belief of mine is reliable.” Once again, we’re just dealing with mental acrobatics trying to justify what one already believes and what thus does not really require any evidence in the person’s mind, as long as they can throw something in the path of objections.
Also, if objective methods indicate nothing mysterious is going on at all (and this is usually always the case), sure, it could always be that there is anyway, because it’s incomprehensible — but, again, why would you be able to reliably tell it’s there, since you can understand it no better? If you want to claim you can understand something better than science, you’d better give some very solid evidence of that instead of saying you can understand it because no-one can. After all, this was supposed to be about humility in face of the unknowable rather than about your somehow knowing better than anyone else.
So: Yes, I do believe you’re wrong about this, because if we can’t understand the matter at all, then nobody’s guesses about it are worth anything, including yours.