Some preliminary thoughts about substances and metaphysical necessitation, by way of Harre & Madden.
Okay, the following is a view (as they say): “The relationship between causes and the effects that they bring about is one of metaphysical necessity, not accidental correlation.” There are alternate versions of the view. In particular (no pun intended), there are different possible sources for the necessity. And of the contemporary thinkers who hold it (or who did when they were alive), or who use language that is suggestive of it, I can’t think of anyone who doesn’t stipulate that the metaphysical necessity in question can be foiled by the intervention of some other cause; it’s always (for better or for worse) ceteris paribus. I say “for better or for worse” since Stephen Mumford (now with Rani Lill Anjum), for example, has always been quick to note that a relationship of supposed necessity that may not actually hold might be thought to be mislabeled.
Still, there is a view, held by some, rejected by others, that: (a) the relationship between causes and the effects that they bring about is one of real, live, this-worldly metaphysical necessity (rather than accidental correlation); and yet (b) the relationship in question does not imply that any token cause necessitates the token outcome to which it is so related metaphysically. I’ll call it the ‘metaphysical necessity view’, in the way of the operative speech genre. (Also, it’s shorter to call it that. Though I could also call it Bob. And maybe I will, since that would funnier than ‘the metaphysical necessity view’ – and shorter too – and funny wins.) I’m interested in Bob in the context of theories in which causation is connected to the display of powers-to-phi, where such powers are thought to involve real, non-metaphorical, non-reducible activity.
Mumford & Anjum are well known for rejecting Bob. Reconstructed (I hope accurately), their charge is that claim (b), above, is incoherent. One cannot say that token causes may not actually issue in the outcomes with which they are metaphysical associated unless one rejects (a). While it is true (they hold) that the relationship between causes and their effects is not one of accidental correlation, it is not true that it is one of metaphysical necessity.
Now, since the major proponents of Bob (or of close relatives) do hold (b), it is clear that whatever it is that they are affirming when they affirm (a) – coherently or not – it isn’t a straightforward assertion of de facto token necessitation. What is it, then? The governing interpretation seems to be that what is being asserted as a matter of ontology is that there exists some kind of base-line necessitation relation between causes and their effects that holds deep down, even though everyone agrees that actual token causes do not necessitate any given token outcome. (Bhaskar, especially, of those who might be counted as being a friend of Bob’s, is at pains to stress that the modal status of a power is that of a tendency.)
I think that this interpretation is a bad reading of Bob. I think this even though in some places even proponents of Bob sound as though they might think that that’s what they mean. Certainly it’s not what anyone should mean, since one shouldn’t both deny and affirm determinism. I also think it although the implicit counterfactual determinism can be sustained by what is (I think) actually meant (and certainly what should be meant). [Note: don’t get hung up on “meant” or “mean” — I am using the words in a non-technical sense, not signalling that anything hangs on anyone’s semantics.]
What, then, might it mean to say, as Harre & Madden do, that it is a matter of metaphysical necessity that, if a substance of the kind ‘human being’ is thrown into a furnace (I know; it’s gruesome), then, in the absence of some other cause coming into play, given the nature of human beings and the nature of fire, that substance will be incinerated? More precisely, what might it mean (other than that one is prepared to affirm p & ~p) to say this and yet to also insist, as Harre & Madden do, that it is not the case that if there is a furnace into which a human being is thrown, then necessarily that human being will be incinerated?
In Harre and Madden’s case, at least, the answer is very clear. The claim is not that there is a relation of metaphysical necessity between raging fires and incinerated substances of the kind ‘human being.’ The claim is that there is a relationship of metaphysical necessity between something’s being a member of the kind ‘human being’ and being such that if it is cast, unprotected, for a sufficient period of time, into a raging fire, it will be incinerated. There is a similar relationship of necessity between fire and the properties of fire. The kind-natures of the given powerful particulars underwrite the apparent counterfactual necessitation underlying the ceteris paribus stipulation, but (a) they don’t deliver de facto necessitation (for the very sensible reasons that Harre & Madden provide, having to do with the potential contributions of other powerful particulars), and (b) it is a reification to think that that the “would otherwise” refers to some underlying causal relation that is somehow being thwarted.
No. As Bob has it, there are two fundamental issues of ontology here: one concerning substances (or objects), one concerning causation. With respect to substances, the claim is that there are powerful particulars of given kinds. The further modal specification is that while it is not metaphysically necessary that any given kind of thing exist, if a given kind of thing does exist, then the relationship between its members and their kind-based properties is one of metaphysical necessity. With respect to causation, the claim is that causation involves displays of the powers of powerful particulars of given kinds, which displays constitute relations of cause and effect amongst said powerful particulars of given kinds. These relations are not arbitrary, but neither are they, at the relevant level of abstraction. presumptively deterministic.
I suspect that, in the case of contemporary analytic thinkers, the temptation to posit the existence of a real but non-actual realm of deterministic necessitation is enhanced by a general squeamishness about substances (or objects), or in any case a distance from them, amongst Anglo-analytic metaphysicians. Once the discussion effectively assumes nothing but a field of properties, here powers, it is easier to lose hold of the proposed neo-Aristotelian picture. The temptation is probably also enhanced by the fact that contemporary thinkers are not trained to think in exclusively this-worldly terms about modality. The habit of going off-world may make it easier for one to imagine that if something would have otherwise happened in this world, that implies that it really is happening somewhere else, if not off-world then here deep down.