Objection 1. It would seem that all other creatures concur in man's last end. For the end corresponds to the beginning. But man's beginning--i.e. God--is also the beginning of all else. Therefore all other things concur in man's last end.
Objection 2. Further, Dionysius says (Div. Nom. iv) that "God turns all things to Himself as to their last end." But He is also man's last end; because He alone is to be enjoyed by man, as Augustine says (De Doctr. Christ. i, 5,22). Therefore other things, too, concur in man's last end.
Objection 3. Further, man's last end is the object of the will. But the object of the will is the universal good, which is the end of all. Therefore other things, too, concur in man's last end.
On the contrary, man's last end is happiness; which all men desire, as Augustine says (De Trin. xiii, 3,4). But "happiness is not possible for animals bereft of reason," as Augustine says (QQ. 83, qu. 5). Therefore other things do not concur in man's last end.
I answer that, As the Philosopher says (Phys. ii, 2), the end is twofold--the end "for which" and the end "by which"; viz. the thing itself in which is found the aspect of good, and the use or acquisition of that thing. Thus we say that the end of the movement of a weighty body is either a lower place as "thing," or to be in a lower place, as "use"; and the end of the miser is money as "thing," or possession of money as "use."
If, therefore, we speak of man's last end as of the thing which is the end, thus all other things concur in man's last end, since God is the last end of man and of all other things. If, however, we speak of man's last end, as of the acquisition of the end, then irrational creatures do not concur with man in this end. For man and other rational creatures attain to their last end by knowing and loving God: this is not possible to other creatures, which acquire their last end, in so far as they share in the Divine likeness, inasmuch as they are, or live, or even know.
Hence it is evident how the objections are solved: since happiness means the acquisition of the last end.
Source: Summa Theologica (New Advent)