Actually there's two questions here; the question I think he's asking and the question you think he's asking. The question you think he's asking is: why is the

Actually there's two questions here; the question I think he's asking and the question you think he's asking. The question you think he's asking is: why is there a limit to how fast light can go? For this we have a reasonably good explanation; it's more or less a consequence of basic geometry once you've understood relativity. The question I think he's asking is: given that we have a value of c why is it that value of c and not some other? For this we have no damn explanation, it's just an arbitrary constant that got baked into the universe for some reason. Perhaps one day we'll understand it in terms of something else, but perhaps it's just as in-principle unanswerable as "so why the fuck is there a universe in the first place?"