Aristotle places great emphasis on understanding causes. "For Aristotle, a firm grasp of what a cause is, and how many kinds of causes there are, is essential for a successful investigation of the world around us." Aristotle uses the famous four causes to explain why questions:
•The material cause: “that out of which”, e.g., the bronze of a statue.
•The formal cause: “the form”, “the account of what-it-is-to-be”, e.g., the shape of a statue.
•The efficient cause: “the primary source of the change or rest”, e.g., the artisan, the art of bronze-casting the statue, the man who gives advice, the father of the child.
•The final cause: “the end, that for the sake of which a thing is done”, e.g., health is the end of walking, losing weight, purging, drugs, and surgical tools.
Understanding these four causes is vital: an explanation which fails to invoke all four causes is no explanation at all. Many causal analyses today look mainly to efficient causes and see final causes as above and beyond causal analysis. Aristotle would see this approach as deficient, not only did he include final causes, but he gave explanatory priority of the final cause over the efficient cause. He did not limit his search of final causes or the goal to the effects of rational agents; even natural causes show design and understanding that design is vital to understanding "the why".
For example, why cannot it be merely a coincidence that the front teeth grow sharp and suitable for tearing the food and the molars grow broad and useful for grinding the food (Phys. 198 b 23-27)? When the teeth grow in just this way, then the animal survives. When they do not, then the animal dies...
Aristotle's reply is that the opponent is expected to explain why the teeth regularly grow in the way they do: sharp teeth in the front and broad molars in the back of the mouth. Moreover, since this dental arrangement is suitable for biting and chewing the food that the animal takes in, the opponent is expected to explain the regular connection between the needs of the animal and the formation of its teeth. Either there is a real causal connection between the formation of the teeth and the needs of the animal, or there is no real causal connection and it just so happens that the way the teeth grow is good for the animal. In this second case it is just a coincidence that the teeth grow in a way that it is good for the animal. But this does not explain the regularity of the connection. Where there is regularity there is also a call for an explanation, and coincidence is no explanation at all.
All quotations are from Andrea Falcon's fine article on Aristotelian Causality.
Darwinism responds with survival of the fittest - animals (and their predecessors) with broad teeth in the front died off because they are unsuited to survival. When we cannot find dental records of such animals, Darwin refers us to the mystery of countless past ages. But at bottom there is no answer to the why; no design. As for atheism, this lack of explanation of "the why" runs deep; to the core really. According to Bertrand Russell "The universe is just there, and that's all." No design in nature, no point to the universe, no afterlife or ultimate goal for man; everything remains ultimately unexplained with regard to final causality. How sad in contrast to the fullness of life Christ offers us.