Probability

One motivation for creationist theories often goes something like this: "Look at the amount of complexity in the human and natural world. The probability of something this complicated happening by random chance is [insert fantastically small number here]. Therefore, it is rational to conclude that life/the universe did not occur by chance, but rather by design." I've always been troubled by arguments of this type. The probability of an event's occurrance is relative to a state of affairs. We know that the probability of a coin landing heads up is .5, given that I flip it. Since we know that Tom is a professor, we can estimate a high probability of his being a liberal. But what presupposed states of affairs are relevant for our theory of the formation of the universe? From our point of view now, we already know that the universe happened, so it's just false to say there's a low probability of its having occurred. That would be as if I flipped a coin, observed it as having landed heads, and then said that there's a 50% chance that the coin landed tails. Let me put the problem another way. The problem for non-creationist origin stories is supposed to be that they rely on something fantastically unlikely to have occurred. But here's a case which I allege to be parallel: I'm currently reading Christine Korsgaard's The Sources of Normativity. Just now, I opened the book to page 61, and discovered the following remarkable thing -- the pattern of the left-most characters in each line on the page, read top to bottom, is "sTvmstvTawcIFseemcuTlormtomibouAanMc'r" Even ignoring punctuation, considering twenty-six letters and the upper/lower-case and italic or non-italic as variables, the probability of that string having occurred on a page by chance is one in (26 * 2 * 2)^38, somewhere on the order of 4.1 * 10^72. But surely that's not remarkable -- it's just what's there. We don't need to posit someone designing the page that way, even though it's fantastically unlikely that it should have turned out just like that. (Korsgaard is a designer for the book, but presumably not for the layout of page 61.) Fantastically unlikely things happen every day -- and we can discover true things that are unlikely to an arbitrary degree just by making them conjunctions (for example, even more unlikely than that string's occurrance is that string's occurrance in a paperback book. More unlikely still, that string occurred in a paperback book on a prime-numbered page! What kind of philosophy am I engaging in with these questions? What authoritative papers and books are relevant? I'm sure these aren't original ideas I'm having, but I've never formally studied anything like them.