from PARTS OF ANIMALS, Book One, Chapter One
                                                            - Aristotle

The causes concerned in the generation of the works of nature are, as we see, more than one. There is the final cause and there is the moving cause. Now we must decide which of these two causes comes first, which second. Plainly, however, that cause is the first which we call the final one.  For this is the reason, and the reason forms the starting point, alike in works of art and works of nature.