George Molnar’s Powers: A Study in Metaphysics appeared in 2003, with a paperback version following recently. The book presents a realist theory of causal metaphysics founded on a detailed ontological treatment of dispositional properties, or powers. Molnar’s work was brought to my attention last fall by an e-mail correspondent, to whom I’m grateful. I plan to present some notes and thoughts about the book over a couple of posts.
The book is a posthumous publication, Molnar having died in 1999. Some brief biographical information is provided in the introduction by Stephen Mumford (see also this webpage [UPDATE: 8 March 2011 - this was a link to a page about Molnar - now gone), as well as in a preface by D. M. Armstrong. Born in Budapest, Molnar and his family escaped the Nazis and he settled in Australia. He became a philosopher and published a handful of metaphysical papers early in his career. Then leftist political activities led him to depart his university post and exit formal academic philosophy for a couple of decades until just a few years before his death. In those years, this book took shape.
According to Mumford, who prepared the manuscript for publication, the chapters which present the main theory were largely complete; the manuscript lacked an introductory chapter and only fragments existed of the intended final chapters on application of the theory of powers to various metaphysical problems. Mumford has provided a helpful introduction, and edited the final fragments into a condensed last chapter.
Molnar’s theory is a realist account of dispositional properties as causal powers. This realism about dispositional properties and causality is in contrast to work in the Humean tradition which would eliminate dispositional properties and reduce apparent causal power to mere correlation. A traditional strategy is to employ a conditional analysis. Rather than ascribe the dispositional property of solubility to X, one simply notes that if X is placed in water, then it will dissolve. Another way to approach eliminating powers is to claim they can be reduced to categorical micro-physical properties (although many would view charge, mass, spin et. al as paradigm dispositional properties). Molnar will defend dispositional properties as real and ineliminable causal powers of objects.
Molnar’s Ontological Categories
A. Tropes. Molnar wants to present a full ontology of powers, so he must answer the question: what kind of properties are they? His answer is that properties are tropes. He thinks that nominalists are right to distrust the idea that properties as universals are real but err in rejecting all realism about properties. Realists are right in their realism, but wrong about universals, which are too inconsistent with naturalism. There are sections discussing the characteristics of tropes in great detail in Ch. 1, which I will pass over for now. I should note that in addition to powers, Molnar will find a need for non-power properties as well, leading to a property dualism.
B. Objects. There is a classic problem with tropes, however, which is explaining how they bunch up in coherent ways. Attempts to posit ways to bundle tropes together without adding something new to the mix are unsuccessful (see my old post with a link to work on this topic by Dr. Bill Vallicella). Molnar bites the bullet and admits objects as an additional ontological category. Powers are powers of objects. (Later in the book, though, he will admit ungrounded powers as well).
C. Relations. In Molnar’s assessment, objects are separable from their location in space-time. This leads him to add relations as an additional irreducible ontological category.
Given these ingredients, at least one ontological category Molnar will not need are “states of affairs” (or facts or situations, etc.), which he criticizes in section 2.3.
Still, I think that one can be more economical yet with regard to the size of the ontological zoo. I’ll say more later after a discussion of powers, but I think an event ontology can improve on an object oriented ontology.