Change, motion, and explanation › What changes when the coffee cools?

Imagine a mug of coffee sitting on a desk. An hour later, the coffee is cooler. It is tempting to say that we have already explained the event once we have named its beginning and end. But that leaves several questions unanswered. What underwent the change? Which capacity made that change possible? What brought it about? And what distinguishes the cooling process from simply being cold?

Aristotle's Physics investigates the principles needed to answer questions like these. Its subject includes growth and qualitative alteration as well as movement from one place to another. It also asks about the conditions under which change can occur: place, continuity, and time. The work joins questions about explanation to claims about the physical world; those claims need to be assessed along with its concepts.

The central proposal is that change can be understood without imagining that something emerges from sheer nothing. Something capable of being otherwise undergoes a determinate process. Yet a capacity, an ongoing change, and a completed result are different conditions. Keeping them distinct helps explain why Aristotle describes motion through both potentiality and actuality, rather than treating those terms as simple opposites.