Dan Little on Mumford and Anjum, re: necessitation


Dan writes:  “My issue with their argument is that I don’t think that logical sufficiency captures what causal theorists have in mind when they assert that the cause brings about its effect with some degree of necessity.”

He concludes:  “So the kind of necessity I would like to attach to causal sequences goes something like this:

  • Given the underlying nature and constitution of the substrate of the field of action and given the constitution of A, we can uncover the active and provoking transitions through which A leads to B in a non-accidental way.

This conception differs from both apparent alternatives — the unvarnished contingency that Hume asserted for causal linkages and the deterministic ‘If A then B necessarily’ logic that some theorists would like to see.”

Hi Dan!  And Stephen and Rani!  And others!

I think that whether or not you will want a third term for the phenomenon in question depends upon whether or not you think something can be a little bit necessary.  Stephen and Rani want to say that, more or less by definition, “necessary” doesn’t admit of degrees.  An outcome is either necessitated or it isn’t.   If the world is such that the outcome will not happen 100% of the time, the outcome is not necessitated.  (One should be careful not to slip into an epistemic register, here.  The issue is not whether we can know anything with with 100% certainty.)

They use the term “dispositional modality” to refer to precisely that middle ground between “random” and “necessary” that you describe aboveRoy Bhaskar introduced the term “normic modality” in A Realist Theory of Science to capture the same intermediate modal condition: viz., that of A leading to B in a “non-accidental way,” as you put it.  Roy emphasized that A necessarily tends to produce B, given what A is: A is not going to stop tending to produce B.  But it does not follow from this that A necessitates B.

Stephen and Rani refer to what I’ve just described as “categorical” necessity rather than “causal” necessity, citing Kant (though Kant of course has an entirely different metaphysics of causation than do powers theorists such as Roy, Stephen and Rani ).  Here we are saying nothing more than that A’s tendency to bring about B is grounded in A’s being A.

For what it’s worth, I can’t actually think of anyone who has written extensively on powers and who holds an activity-based conception of causal powers who thinks that powers-based causes necessitate their effects.   Roy didn’t; I don’t think Nancy Cartwright does (that’s the whole point!); Brian Ellis doesn’t; Stephen and Rani don’t.

And neither, it would seem, do you!  Yay!


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