>To argue that action that we understand / perceive as coming from free agents is only a response to other movements, and anything about this that might be perceived as "free" is mere illusion, is to undermine the legitimacy of both language and argument - and therefore the position is self-contradicting, ergo it is irrational. Bingo. You can't tell people that you can't say true and false things, else why should they take seriously what you're telling them? Sophistry! Feser's *Scholastic Metaphysics* is damn good as well, for anyone that prefers more up-to-date language, as well as the elaborations that the Scholastics added. There are some people doing really serious Scholastic metaphysics in professional philosophy, but Feser is able to make it approachable. That's just my opinion.