It is a paradox. For example those who are of a Judeo-Christian faith admit that it is extremely difficult, if not beyond current human capacity, to comprehend a Creator that has no beginning. We know nothing in our experience that exists that did not "come into" existence, and we base all we logically know on what we can understand from what we experience, don't we?
Yet perhaps, and just perhaps--not objectively speaking, because at this point we are speaking highly theoretically and, as understood in academic terms, in reference to a religious "revelation," meaning developing theories based on the premise that such revelation is true (i.e., if what God says is true, then based on that how is such-and-such possible, etc.)--we answer our own question when we ask it.
We end up with this "headache" because we admittedly cannot wrap our minds around it. It is contrary to how we use logic. We start bumping into very hard corners in our minds that we never knew we were there, and we become overwhelmed. To me when that happens I see myself as one of those cartoon robots that someone gives a suggestion to that goes beyond his program, and that this somehow causes him to self-destruct over the paradox such a suggestion makes.
I get the same headache. Everyone does, regardless if it is true or not. It does not compute. Period.
Part of the reason this happens is that in order to function we can't sit around all day thinking about being on a small speckle of rock hurling around the void with the possibility that today is the day the equation proves true and we get stuck by an even bigger rock and go BOOM! It's gonna happen, sooner or later. Even if it doesn't happen to the entire planet, something big enough can still fall out of the sky and that "pretty falling star" some kid is making a wish on is landing on our head and snuffing us out. "Thanks for the wish, kid. I hope you're happy!"
We can't do that. Otherwise we won't live our lives. We have to settle on some things always being at constant otherwise we won't get into cars (because sooner or later there might be an accident and we might die) or into planes (because sooner or later there might be a crash and we might die) or even eat food (because sooner or later we might eat something poisoned and we might die). No, we trust in the constants.
Same thing with this. It's hard to grasp this mainly because we generally base our logic on what we can experience. To go against experience is illogical. To then realize that our experience is relative (for example by accepting this theory) we can go bonkers.
Of course, this theory also exists in science. It's called the "theory of relativity." You know the one that if you could travel the speed of light that your wrist watch would stop? It would, really, and you would witness it. How?
It will give you another headache, but this one you can blame on science and not religion, how is that? Read up on the hard version (from Wikipedia) and the easy one (For Dummies) below.
Then go about living your life, realizing that what we learn about God is not based on experience but on reliance that his self-revelation is true...that is if it really came from HIm as He says it does.
And take a couple of aspirin, mindful to write me back if you ever do totally comprehend any of these time relativity things from either science or religion. I'm so dizzy now I need to lie down.