Actually Doc, I haven't read any Douglas Adams. I come up with the potty ideas myself!
I would be interested in why you thought it was the case. Does he cover this topic?
I have little knowledge of literature. It is a gaping hole in my knowledgebase.
I would argue that you cannot approach infinity, because however far you go, you are always infinitely far away from infinity. There is more to infinity than meets the eye! In fact, when you think about it, the jump from an extremely large number to infinity is a binary jump. An infinite jump. There is no intermediate stepping stone number.
I agree, approaching infinity doesn't make the impossible happen. But it does make the exceedingly improbable almost certain. e.g. the probability of a coin toss coming up a trillion heads in a row is exceptionally unlikely. However, with an infinite number of coin throws, it is 100% certain to happen. In fact, I am wondering if it is possible for an infinite number of heads to come up given an infinite number of coin throws. But then that would exclude the possibility of a trillion consecutive tails coming up. So intuitively, I would say you cannot have an infinite number of coin throws coming up heads. But it is indeed a physical possibility (or is it?). And if something is a possibility, perhaps the infinitely improbable becomes infinitely probable. So I have arrived at a paradox, I believe. Interesting.
[Edit: It could be that the distinction is between infinitely improbable and very improbable, the latter being 100% certain and the former being impossible. Oh my head hurts!]