Scientific knowledge provides causal explanations of real kinds of things. Aristotle asserted that there are four causes: formal, material, efficient, and final. The formal cause of your dog is what makes the animal a dog—it is its dog essence. The material cause of the dog is the physical stuff of which it is made—its matter. (Aristotle believed that matter or physical reality is the same in all things but uniquely informed by their specific forms.)

The efficient cause of the dog is its birth and the food and water it consumes. The final cause of the dog is its ultimate purpose or function as a dog—its full development as a dog and its ability to be a loyal friend and helper to human beings in general, and because it is your dog—”yours” in particular. Form is the actuality of a substance and matter is its potential. The particular puppy you first brought home had the physical potential to become the fully excellent creature it grew into.