I’ll be the first to say that a lot of physics and a lot of metaphysics goes right over my head. Whoosh. Modern analytic philosophy, which is what most folks mean when they say metaphysics, is about as comprehensible to me as advanced mathematics (I’m terrible at math). A lot of modern physics, at least the mathematical parts (which is a lot) is the same – whoosh.
However, I do try and keep up at least somewhat with the latest developments of the broader ideas and underpinnings of metaphysics and physics – especially physics, which is way more metaphysical than a lot of folks think it is. Philosophy of physics and the broad metaphysical ideas behind and under modern cosmology are just as important, and in my mind way more interesting, anyway.
I say all this to pick a fight with something Tim Maudlin says in his great book, ‘The Metaphysics within Physics,’ :
‘Metaphysics is ontology. Ontology is the most generic study of what exists. Evidence for what exists, at least in the physical world, is provided by empirical research. Hence the proper object of most metaphysics is the careful analysis of our best scientific theories (and especially of fundamental physical theories) with the goal of determining what they imply about the constitution of the physical world.’ (p. 104)
Now, it should be fairly obvious the issues here: the definition of ontology. Ontology is not the study of what exists, ontology is the study of being, or existence (you can be real anal and dispute whether or not those two words mean the same thing. I’m not going to). Being as such, not this or that particular thing that has being – or existence as such, not this or that thing that happens to exist. Being qua being. This is a pretty significant thing to get wrong.
A more concrete example: metaphysics studies how it is that change is possible (Parmenides, Heraclitus, Aristotle) and not this or that example of change (a chemical reaction, for example). What Maudlin does is to shift metaphysics from being the study of the absolute fundamentals of reality to a slightly more abstract form of empirical science, which analyzes various empirical theories. That isn’t metaphysics, that is just normal thinking.
In a nutshell, Maudlin’s scheme is that we derive metaphysics from physics, and further, ontology from physics. Our notions of existence comes from physics. Earlier in the same volume:
‘First: metaphysics, i.e. ontology, is the most generic account of what exists, and since our knowledge of what exists in the physical world rests on empirical evidence, metaphysics must be informed by empirical science.’ (p. 78)
I’m tempted to say that simply knowing what exists gives us no knowledge past bare sensory knowledge of particulars, which doesn’t really lead to knowledge of any kind, which is what Maudlin is setting out to do by analyzing various theories. But why restrict our knowledge of what exists to the physical, as Maudlin implicitly does? Twice above he says that whatever exists in the physical world is supported by empirical, or physical evidence. But that’s only trivially true – obviously, if something exists in the physical world, it will have physical evidence. But it doesn’t follow from that that the only notions of existence, or what exists comes from the physical world.
This seems to be a tangled way of thinking, which has its origin in Maudlin’s confusion of what metaphysics is. Now, as I said above, this isn’t my game. Analytic philosophy ain’t my thing, so it’s possible I’m quite wrong in my analysis. But what I see, in another nuthsell, is (a) a confusion of terms (ontology as the study of what exists), which leads to (b) the idea that our only knowledge of what exists is physical. To make ontology the study of what exists is to make metaphysics and ontology, as stated above, a slightly more abstract brand of empirical science.