Real Dispositions in the Physical World

[Laird]

A Powerful Theory of Causation

S. Mumford & R Anjum

Cross-posting my response to this paper from a post in the Free will re-redux thread:

I was not convinced by their "argument against necessity", which runs as follows:

"Let us call a group of polygenic causes C1, ... Cn and assume that there is a case in which together they produce the effect E, the match lights. Nevertheless, it can be claimed, had all of C1, ... Cn occurred but also some interfering condition I been present, such as a gust of wind, then E might not have occurred. We are taking I to be a real natural or physical possibility, rather than a mere logical one. This shows that C1, ... Cn, although they caused E, were nevertheless consistent with E not occurring. Therefore, C1, ... Cn do not necessitate E, even if as a matter of fact they do cause E."

I wasn't convinced because I think it remains open to necessitarians to respond with this:

"Although we allow that adding I to C1...Cn could conceivably prevent the occurrence of E, and that in that sense, C1...Cn do not necessitate E, this situation nevertheless remains consistent with another, and more important (to us), sense in which a given combination of causes does necessitate whatever effect follows: that being the sense in which the contribution each causal power makes, and the manner in which these contributions are summed, is necessary.

"This is supported by your own framing, in which you write (bold emphasis added by us): 'That powers are pleiotropic means that they make the same contribution to any effect of which they are a cause. The same power always makes the same contribution, when it manifests'. In this context, 'always' is a synonym for 'necessarily', and since the 'vector addition' you describe by which powers add or subtract towards any final effect is the only possible means for arriving at that final effect, it, too, is in the sense we intend 'necessary'.

"Thus, although in one sense you have demonstrated that causes do not necessitate their effects, in a sense more important to us, and equally physical, you have not."

It's partly a matter of semantics, but not entirely.

That said, I think that the approach this paper describes of thinking of causality in terms of "dispositional powers" is useful (in the context of free will)