Katzav on the limitations of dispositionalism

Abstract

Joel Katzav (2004) presents what seems like powerful case against dispositionalism. For his argument purports to show that the principle of least action cannot be grounded in the dispositional properties of objects, as the thesis of dispositionalism requires. Therefore, there is at least one law of nature that needs to be independently grounded. Moreover, this law is a fundamental one. For without the principle of least action, or some general principle of equal power, the specific dispositional properties of things could tell us very little about how these things would be disposed to behave. I think that Katzav is right about this. However, I am not about to recant what I have said in my two major publications on essentialism (Scientific Essentialism, 2001 and The Philosophy of Nature, 2002. Hereafter, SE and PN). For I have long been aware of the problem posed by global principles, such as those of least action, conservation of energy, Pauli exclusion, and so on, and of their fundamental importance in physics. Indeed, I went to a great deal of trouble in these two books to explain carefully how these general principles could be accommodated within the framework of an essentialist theory. Naive dispositionalism is Katzav's real target. It is, as he says, 'the view that the world is ultimately a conglomerate of objects and dispositions' (206), and that all changes in the universe are due to these dispositions being triggered by circumstances. The dispositions of things (and the circumstances that trigger them) must therefore be regarded as 'the ultimate ontological units that explain events' (206). A more sophisticated dispositionalist takes the view that how things are disposed to behave depends also on what kinds of things they are, what kinds of properties they have, and how these kinds of things and properties are placed in the natural kinds hierarchies to which they belong. For the more general laws concerning these things all depend on the more general kinds which they instantiate. But Katzav says nothing about the natural kinds structure of the world that is postulated in SE, nothing about the ontological dependence relationships that necessarily hold amongst these kinds, and nothing about the explanation that is proposed in SE, and developed more fully in PN, of the corresponding hierarchies of laws of nature. There are three hierarchies of natural kinds postulated in SE, a hierarchy of natural kinds of objects or substances, one of natural kinds of events or processes, and one of properties or relationships (which I sup-