6.3 Natural laws?

There are two ontological approaches to the question of natural laws, as we first saw in Chapter 4. The first is to regard all behavior of objects as governed by universal laws. In physics, for example, such universal laws are often written mathematically, and it is claimed that all changes must be in accordance with these laws. Any deviation from the predictions of the laws would indicate either that the initial conditions used in the prediction were not correct or that the laws could not have been correct. Maybe some influence was present that was not allowed for in the law, in which case it was not universal after all, and another (more) universal principle would have to be found.

A second dispositionalist approach is to consider that objects and people are constituted of propensities and desires respectively. Then, how these behave in the future is just a consequence of their particular kinds of propensities and desires, along with the forms and circumstances in which they find themselves. In this second approach there is no need for any natural law over and above the responses generated by the dispositional natures of things.

It is this dispositionalist approach which is advocated in this book. In the contemporary literature in the philosophy of science, it has been explored extensively in books by Mumford (1995), Molnar (2003), and Bird (2007) within the framework of what they call ‘dispositional essentialism’. This was the essentialism introduced at the start of Chapter 4, and I owe much to the expositions of those three authors as well as to the other authors listed in Section 4.3. This impetus to regard the dispositional properties of objects as ontologically prior to any universal laws which might appear to describe their behavior can be traced back to a kind of Aristotelian approach to natural ontology. It contrasts with a Platonic approach wherein universal principles are viewed as somehow more real than the objects which they govern.

In this second approach, now adopted, if a deviation from predictions is found, then we look for new circumstances for the manifestations of existing dispositions. If that does not explain events sufficiently, then we consider the existence of a new disposition of the participating objects. We are able to consider objects with new and distinct dispositions. We can consider influences of new objects with unforeseen propensities if we cannot explain those dispositions in terms of the internal structure of micro-dispositions. There are no ‘rigid universal laws’ which prohibit novel events by rendering them logically impossible within the framework of a universal theory.

In practice, however, science looks for classes of dispositional properties such as of mass, charge, spin, etc., so the differences with analyses based on natural laws are not always dramatic. Nearly all of the existing scientific principles can be adopted into a dispositional ontology with only a very slight loss of predictive capabilities. This adoption is beneficial because there is generally an increase in explanatory capabilities. We now see how the behavior of objects follows from their own being or substance since that substance is identified as its set of fundamental dispositions.