Video from The Thomistic Institute
Teleology
“The chicken does not exist only in order to produce another egg. He may also exist to amuse himself, to praise God, and even to suggest ideas to a French dramatist.” ― G.K. Chesterton, What's Wrong with the World Following Aristotle, St. Thomas Aquinas speaks of the end or finality of a thing ― that for the sake of which a thing exists. Aquinas notes the innate directedness of all things. For example, in the world of plants, the tree seeks to grow upward toward the sunlight. Aquinas sees an intelligent source, which he calls God, as the animator and sustainer for this intelligible order. Teleology (Aquinas 101) - Fr. Dominic Legge, O.P." from video introduction.