mclean%nrl-css@sri-unix.ARPA (07/22/85)
From: John McLean <mclean@nrl-css> > The term meta-physics does not mean what you think it does. Usually > written without the hyphen, it refers to a particular school of (non-modern) > philosophy that has no particular relationship to physics. Perhaps > someone else can give us an authoritative definition. > > It would be nice to have a term for speculation on questions like > 1. Does there exist a finite theory that completely describes the > fundamental behavior of matter in the universe? > 2. Is there a simple and elegant mathematical formulation of this > theory? Why should there be? > 3. Can we guess constraints on what this theory must be like? > (Many general relativity enthusiasts would say yes.) The questions you ask form part of the subject matter of metaphysics, and in general metaphysics does have a deep connection to physics. Aristotle's original question in the METAPHYSICS is "What is being?" which quickly turns into "What is substance?". The relation to physics comes to light when we learn that one of the distinguishing properties of substance is that it is subject to description by what look like physical laws. In other words, part of Aristotle's question is what collections of objects are appropriate for scientific study. He was aware that not just any old collection (e. g., the contents of my pocket or pieces of string exactly 6 inches long) was suitable. When you remember that Aristotle was inventing several branches of science, it was an important question. The question about "What general constraints lie on theory formulation?" comes right out of Kant's CRITIQUE OF PURE REASON. Kant figured that any constraints on science must come from us and the fact that the objects of science are in some sense created by us (we pick out what collections are appropriate for scientific study). The CRITIQUE OF PURE REASON aims at finding these constraints by looking at us. One such constraint Kant argued for was that since we must locate events in time (his argument why we must do this are hairy), we must view events as being causally related. The difference between saying that A happened before B objectively (as opposed to I just happened to experience A before B) is that they are causally related. If you downplay this a bit and say that A objectively occurs before B only if they have the potential to be causally related, you get what looks a lot like special relativity. For the philosophically minded, you can also see in this position Kant's answer to Hume's denial of objective causation. You can't say A happened before B and then question causality. You've already presupposed it in your statement. The point I am trying to get across is that metaphysics is not empty, it's just very hard. Unfortunately, most people think that anybody can do it or that reading it should be easy. Imagine how frustrating it would be if every jerk you met in a bar had a similar view about quantum mechanics. John