Why does causality work? (OR: What is change?) Modern physics offers a powerfully sophisticated description of the behaviour of matter, including extremely complex maths that gives us highly reliable predictive power. But, when you peel back the layers of that onion, what you find are wispy metaphors and “placeholder” terms at the core. The most popular, of course, are the terms “energy” and “force”. But, what is that? The common example of billiard balls provides a good illustration.
In the Physics, Aristotle says that we aim at understanding, which he says is to be able to give a full account of “the how and the why of things coming into existence and going out of it”. In other words, to understand something is to be able to give an explanation of how and why a thing changes. That explanation is what Aristotle means by ‘cause’. Today, thinking of explanation in terms of causes is not an alien notion.