Psychology necessarily deals with dispositions and not just with what events actually occur. Even the behaviorists recognized that they should study tendencies to behavior and not merely the behavioral events themselves. Our question will concern the ontological status of these tendencies or dispositions.
Ryle (The Concept of Mind, 1949) takes the view that dispositional ascriptions “assert extra matters of fact” and claims that they are only “inference-tickets which license us to predict, retrodict, etc.” He quite explicitly denies that one should look for either causal or mechanistic explanations of the dispositions. This holds even in cases in physics and chemistry where there are explanations in terms of constituents and their propensities to attract and repel each other. His restriction against looking for explanations in terms of internal dynamics is, fortunately, largely disregarded in scientific practice.
We could interpret psychological dispositions in the same way that physics interprets potential energy. Bawden, for example, claimed in 1947 that “the role of the psychical in relation to the physical (in the living organism) is essentially the relation of the potential or incipient to kinetic or overt action.” I respond that potential energy is (again) a kind of disposition that must in some way exist, as a substance.
In cognitive psychology it is a common starting point that mental activities consist of functions of information-processing modules, engaged, for example, in signal or symbol processing. This description refers only to the structural or formal aspects. Admittedly, structural changes are described, but no specific powers or dispositions for those processes are admitted. This is inadequate, however, from the point of view of any causal realism. Any account based on computation can only be realistic if it at least allows that the hardware implementations use objects with powers, as then physical symbol processing is consistently possible. Remember (from the previous post), that dispositions/causes remain absolute different in category from forms and information.
So, what is the actual nature of the dispositions that are operative in mental activities? Are these just aggregations of physical dispositions, or are there ‘true mental dispositions’ that are distinct from the physical? If the later were true, we would ask what impact the true human substances have on cognitive processing, since they will have their own characteristic powers and propensities not necessarily present in computers. The issue in psychology is thus whether the dispositions and powers that constitute the substance for mental objects and processing are related to the dispositions and powers manifest in the mind itself. I am thinking specifically of the emotional and motivational dispositions that make up the apparent life of mental feelings and intentions. These are powers that appear on first phenomenological analysis, so psychology should consider whether they could be the first ‘more fundamental’ underlying stuff of which cognitive and symbol processing is the activity.
According to Descartes, the soul (mind) is a substance and thought is the mode of its operation. This might explain what constitutes minds. However, Descartes does not offer a dynamical account to explain the operations of the soul. (On the contrary, he was pleased that the rational soul, as he conceived it, was completely outside the scope of the new empirical sciences and could be made subject to the edicts of ethics and religion.) In the end, Descartes never discusses reasons for the details of mental powers or capacities. That is what we want really to discover!