Natural Necessity, Objective Chances and Causal Powers :: Philosophy Philosophical Essays

Natural Necessity, Objective Chances and Causal Powers ABSTRACT: Are the relations between the property of a thing and its related disposition to react in certain ways, and between the triggering of that disposition and the consequent effect, necessary? Harrà © and Madden, in their analysis of causal powers, said they are, but their arguments are not persuasive. Humeans like Simon Blackburn deny it. I criticize the Humean position, and argue afresh for their necessity. I note that David Lewis' analysis of causation requires their necessity, though as a confessed Humean he has not admitted this. There is an interesting convergence among several recent theories of causation. They describe causes as events of a kind which increase the objective chance of events of other kinds, which are their effects. The theories I have in mind are those of David Lewis (1986, 1994), D.H. Mellor (1995), and Peter Menzies (1996). They attribute various other properties to causes, but all agree that this is an important and necessary fact about them. Thus, dropping a crystal wine glass onto a hard floor can be said to have caused it to shatter because it increased the probability of its shattering at that time, since whenever a piece of crystal glass is struck by a hard object, it will very probably shatter. Such generalizations relating cause and effect can be understood as being true of something because of one of its properties. For instance one can say: if something has the molecular structure of crystal glass, then if it is hit by a hard object it will very probably shatter. The generalization relating cause and effect can then be seen as a disposition of the thing whose property makes it true. In this case it amounts to saying that things which have the molecular structure of crystal glass are fragile. More generally, the generalizations involved in causation are of the following form: if something has a certain property, then if it comes into a certain relation with something else, it will result in another event, with a certain objective probability. Call this generalization [G]. This generalization looks very much like the analysis of causal powers offered by R.Harrà © and E.H. Madden (1975). They defined the causal power of a thing in terms of its disposition to behave in certain ways in certain circumstances because of its nature. They wrote: "'X has the power to A' means 'X will or can do A, in the appropriate conditions, in virtue of its intrinsic nature' (p.