One of the many things I like Aristotle for is his clear concern for what are sometimes called “secondary” causes. As usual with Aristotle, “cause” means any kind of explanation or determining reason; explanation is in general not univocal; and things are the way they are due to the combination of many causes. Secondary causes for Aristotle play an irreducible role in the overall determination of things. This is part of what I recently called the dignity of finite beings.
The way in which secondary causes operate is pluralistic; there is no single, seamless matrix of causality in the world. Instead we have a superabundance of meaning. Determination is always grounded in actuality, but actuality is never the whole story. We get a better grasp on things by taking counterfactual potentiality into account.
Secondary causes may be either “moved” or “unmoved”. If the form of an animal’s leg joint counts as an unmoved mover, the number of unmoved movers in the world is truly vast. There are also a vast number of moved movers.
Even though there is a great deal of practically meaningful determination in the world, neither God nor physics comes anywhere near completely determining human reality. The world has both real determination and real play in it. See also What and Why; Interpretation).
The Postmodern Peripatetic 