In the article "Aristotle on Causality" in the Stanford Encyclopedia of Philosophy we read:
Here Aristotle recognizes four types of things that can be given in answer to a why-question:
- 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.
Now, bronze is an alloy consisting of copper and tin. So why isn't the material cause of the statue simply copper and tin?
At least copper and tin are chemical elements and so far more fitting as a fundamental material. Of course Aristotle didn't know that, but he knew that bronze was just a "mixture".
Or one could even ask why the material cause of the statue isn't just "many protons, neutrons and electrons"?
How does Aristotle decide how 'deep' we should go to find our material cause?