Online research in philosophy

In this paper I examine the role of dispositional properties in the most frequently discussed interpretations of non-relativistic quantum mechanics. After offering some motivation for this project, I briefly characterize the distinction between non-dispositional and dispositional properties in the context of quantum mechanics by suggesting a necessary condition for dispositionality – namely contextuality – and, consequently, a sufficient condition for non-dispositionality, namely non-contextuality. Having made sure that the distinction is conceptually sound, I then analyze the plausibility of the widespread, monistic ontological thesis about the reducibility of dispositional properties to categorical properties in the context of the philosophy of quantum mechanics. I conclude that with the exception of Bohmian mechanics, the other “minimally realist” views of quantum mechanics require essential dispositions, i.e., dispositions of a non-reducible kind. Interestingly, seen behind the lenses of dispositionalism, Bohr’s and Bohm’s interpretations of quantum mechanics are much closer than it is usually recognized, a fact that could teach us something about the way the quantum world is.

Dispositions are essential to our understanding of the world. IDispositions: A Debate is an extended dialogue between three distinguished philosophers - D.M. Armstrong, C.B. Martin and U.T. Place - on the many problems associated with dispositions, which reveals their own distinctive accounts of the nature of dispositions. These are then linked to other issues such as the nature of mind, matter, universals, existence, laws of nature and causation.

What is it for a property to be dispositional? To answer this question, we can try appealing to the special relationship that dispositions appear to have with modal facts. This is the strategy of modal accounts of dispositionality, which have an important philosophical pedigree.1 For example, consider the following schemas, where for any ‘d’ that names a disposition, one can replace ‘M’ with a purely modal sentence: A1. Having d [a priori] entails M. A2. d is the modal property of being such that M. A3. d is the second-order property of having a property partly in virtue of which M.2 Corresponding to each schema there is a modal account of dispositions. According to what I will call consequentialism, dispositions can be distinguished by modal entailments like A1; according to modalism, dispositions are a special kind of modal property specified by A2; and according to second- orderism, dispositions are a special kind of second-order property specified by A3.

There has been much discussion of powers or real dispositions in the past decade, but there remains an issue that has been inadequately treated. This concerns the precise modal value that comes with dispositionality. We contend in this paper that dispositionality involves a non-alethic, sui generis, irreducible modality. Dispositions only tend towards their manifestations; they do not necessitate them. Tendency is, of course, a dispositional term itself, so this last statement offers little by way of illumination. But given our thesis on the irreducible nature of dispositionality, we maintain that it cannot be explicated correctly in non-dispositional terms. Nevertheless, we all have experience of dispositionality at work, through the exercise or our own powers and the action of other powers upon us. The notion of dispositionality that we acquire is one that involves a modality stronger than pure contingency but weaker than necessity. The recognition of this distinct modal value for dispositionality is one of the biggest oversights in the growing literature in the area. Yet it is there for all to see in even the most mundane example.