The Importance of Teleology

If Aquinas is right, then nature is teleological. It's goal-oriented - not perhaps in the sense that someone has a plan for it. We can also speak of the telos of an organism in a sort of adapted way. Think about that squirrel again. Is it part of its nature to have a tail? Be careful how you answer. Saying no just seems wrong, doesn't it? Obviously having a tail is part of being a squirrel. It might even be the most glorious part. If all this is correct, then there is a close connection between the goodness of a thing and the category or kind that it belongs to.