              In this argument Aristotle seems to introduce as a phainomenon that nature exhibits regularity, so that the parts of nature come about in patterned and regular ways.   Thus, for instance, humans tend to have teeth arranged in a predictable sort of way, with incisors in the front and molars in the back. He then seems to contend, as an exhaustive and exclusive disjunction, that things happen either by chance or for the sake of something, only to suggest, finally, that what is ‘always or for the most part’—what happens in a patterned and predictable way—is not plausibly thought to be due to chance. Hence, he concludes, whatever happens always or for the most part must happen for the sake of something, and so must admit of a teleological cause. Thus, teeth show up always or for the most part with incisors in the front and molars in the back; since this is a regular and predictable occurrence, it cannot be due to chance. Given that whatever is not due to chance has a final cause, teeth have a final cause.