Philosophers have perhaps more often assumed the Principle of Sufficient Reason than argued for it. Furthermore, this assumption has, in recent years, fallen out of favor due to the PSR’s allegedly unacceptable consequences. Recently, however, the PSR has been defended by Alexander Pruss and Michael Della Rocca. Pruss and Della Rocca both argue that (a version of) the PSR is a presupposition of reason. Pruss defends a version of the PSR restricted to contingent truths and consistent with libertarian free will and indeterminism is physics as a presupposition of our scientific and ‘commonsense’ explanatory practices. Della Rocca argues that the metaphysicians who deny the PSR implicitly make use of an unrestricted PSR, applying even to necessary truths, in other metaphysical arguments. Both arguments depend crucially on the claim that there is no weaker principle which is non-ad-hoc and justifies the relevant practices. In her contribution to The Puzzle of Existence, Shieva Kleinschmidt argues that both defenses fail.
Kleinschmidt’s general strategy is to outline contrasting cases – those in which admitting in-principle inexplicability seems to be an option, and those in which it does not – and argue that a non-ad-hoc descriptive account of this distinction can indeed be given.
Kleinschmidt’s primary focus is on Della Rocca, but compared to Pruss Della Rocca gives weaker support to a stronger conclusion. Della Rocca argues that if the unrestricted PSR is not true, then we cannot justifiably rule out certain metaphysical positions which we find intuitively implausible. However, not everyone finds the ‘brutal’ or ‘primitivist’ positions unpalatable in the way Della Rocca supposes (see Markosian). Furthermore, it would not be the end of the world if we were forced to conclude that many of the epistemic practices of analytic metaphysicians are in fact unjustified. Pruss, on the other hand, argues from commonsense and scientific explanatory practices. He asks, for instance, why it is that, when investigating a plane crash, no one takes seriously the hypothesis that the plane crashed for no reason at all. A position that undermined this kind of ordinary, everyday explanatory practice would be in much bigger trouble than a position that said analytic metaphysicians were out to lunch.
Now, Kleinschmidt does talk about the kind of everyday cases with which Pruss is concerned: “For instance,” she writes,
suppose we find small blue handprints along the wall, and we notice that the blue frosting is gone from its bowl and some is on the hands, face, and torso of a nearby five-year-old. When wondering what happened, we will not be tempted even for a moment by the alternative the child wishes to bring to our attention, namely, that the handprints are on the wall for no reason, that they are simply there (p. 67).
Again, someone who was forced to deny that our ordinary process of explaining the handprints was well-justified would be in much bigger trouble than someone who thought our metaphysical reasoning defective. Perhaps the reason for this is that Kleinschmidt herself belongs to the group of metaphysicians targeted by Della Rocca’s argument.
Della Rocca complains that these metaphysicians use the PSR when it suits them and ignore it the rest of the time. Kleinschmidt, however, thinks that this alleged inconsistency shows that Della Rocca has misunderstood the methodology employed by these metaphysicians, for there are indeed cases where (at least some of) these metaphysicians are willing to accept unexplained (and unexplainable) facts (whether necessary or contingent). These hypotheses are not ‘off the table’ in the way the hypothesis that the blue frosting is on the wall for no reason is off the table. In particular, Kleinschmidt describes in detail two contrasting cases: in standard fission cases, the view that it is simply a brute fact that either Lefty or Righty is identical with the pre-fission individual is rarely taken seriously, but in the Problem of the Many, especially as applied to human bodies, brute fact views have been more popular.
This, however, does not get to the bottom of things, for the common core of the arguments of Pruss and Della Rocca is the contention that no weaker principle than the PSR will justify our practice of treating these hypotheses as off the table in the cases where we do so. In other words, if we reject the PSR, then we ought to take the hypothesis that the blue handprints are on the wall for no reason seriously, but surely we ought not to take that hypothesis seriously, so we’d better accept the PSR.
It is only in the last three pages of her chapter that Kleinschmidt addresses this contention directly. She proposes that the claim that explanatory power is a truth-tracking theoretical virtue is sufficiently strong to account for our explanatory practices. “So, for instance, in the handprint case, we reject the theory that the handprints simply appeared for no reason, because we can see how some explanations might go, and some of the explanations are such that endorsing them won’t have disastrous consequences” (77). This, she argues, explains our explanatory practices: we take explanatory power to be a very important virtue in theory choice, so that we do not accept theories that render certain phenomena inexplicable unless we are backed into a corner.
As Kleinschmidt recognizes, this is really only the beginning of a response to Pruss and Della Rocca, for the core problem is not one of description but one of justification. Della Rocca, for instance, explicitly admits that metaphysicians are not consistent in rejecting unexplainables; this is precisely his complaint. He says that this inconsistent practice cannot be justified. Kleinschmidt recognizes this problem, but all she has to say about it is that there is considerable difficulty, as well, regarding the other features (e.g., parsimony) we take to be truth-tracking theoretical virtues.
Insofar as Kleinschmidt has helped to make clearer what our actual explanatory practices are, and shown that a descriptive account need not be radically disunified and ad hoc, this is progress. But the fact is, it is not really an answer to the Pruss-Della Rocca argument for, unless the treatment of explanatory power as a truth-tracking theoretical virtue can itself be justified, no method of justifying our explanatory practices in the absence of the PSR has been made to appear. On the other hand, perhaps Kleinschmidt should be regarded as having shown that those who continue to be untroubled scientific and/or ontological realists despite recognizing the difficulties involved in explaining why the features we regard as theoretical virtues should be regarded as truth-tracking might as well continue to be untroubled deniers of the PSR despite recognizing the difficulties raised by the Pruss-Della Rocca argument, for those difficulties are, essentially, the same. On the other hand, the reasonableness of this untroubled attitude could certainly be called into question.
Finally, it should be noted that Kleinschmidt’s formulations of the virtue of explanatory power are quite strong. She says we are willing to accept unexplainable propositions only when the consequences of refusing to do so are ‘disastrous.’ Now, unless one thinks either (a) that positing a necessary being is itself disastrous, or (b) that contingent facts cannot be explained in terms of a necessary being (i.e. that the modal collapse problem cannot be solved), this principle will still be strong enough to support the argument from contingency for the existence of a necessary being. (Personally, I think (a) is silly but (b) presents a deep and tangled problem.) In short, it seems likely that, even if we accept Kleinschmidt’s conclusion, we can still overcome the parsimony worries I discussed last time.
(Cross-posted at blog.kennypearce.net.)
In his contribution to Goldschmidt’s The Puzzle of Existence, Graham Oppy argues that, “as [a] hypothes[i]s about the contents of global causal reality” (p. 51), naturalism is ceteris paribus preferable to theism. Oppy’s strategy for defending this claim is to consider three hypotheses about the structure of global causal reality, and argue that naturalism is superior to theism on each hypothesis. Here are his three hypotheses:
- Regress: Causal reality does not have an initial maximal part. That is, it is not the case that there is a part of causal reality which has no parts that stand in causal relations to one another and (b) is not preceded by some other part of causal reality which has no parts that stand in causal relations to one another.
- Necessary Initial Part: Causal reality has an initial maximal part, and it is not possible that causal reality had any other initial maximal part. On the assumption that the initial maximal part involves objects, both the existence and the initial properties of those objects are necessary.
- Contingent Initial Part: Causal reality has an initial maximal part, but it is possible that causal reality had some other initial maximal part. On the assumption that the initial maximal part involves objects, at least one of the existence and the initial maximal properties of those objects is contingent (p. 49).
According to Oppy, given Regress theism has no explanatory advantage over naturalism, since both appeal to infinite regress, but naturalism is more parsimonious than theism, hence it is preferable.
The idea that causal reality has an initial part, whether necessary or contingent, might be thought most favorable to theism, but Oppy thinks the case here is really no different than Regress. The reason for this is simple: he doesn’t see why an initial supernatural state is any better, from an explanatory perspective, than an initial natural state (regardless of whether we take the initial state to be necessary or contingent). So, from an explanatory perspective, the hypotheses are again equal, but from a simplicity perspective naturalism wins again.
In my last post, I promised to return to O’Connor’s discussion of the ‘all things considered’ preferability of theism to naturalism. O’Connor concedes Oppy’s claim (in previous work) that naturalism is preferable in terms of parsimony, but insists that “Naturalism simply is not a rival explanatory scheme for existence to Theism” (p. 39). In other words, naturalism, according to O’Connor, does not even try to explain what theism tries to explain. What Oppy gives in his article here is an “anything theism can do naturalism can do better” retort. If the theist posits a necessarily existing supernatural being, naturalism can posit a necessarily existing natural state/being. If the theist posits a contingently existing supernatural being, the naturalist can posit a contingently existing natural being.
Now, as Oppy concedes (p. 51), there is some difficulty about this natural/supernatural distinction. But what Oppy essentially has in mind, is that we are better of positing ‘more of the same’ than positing something totally different (like a God).
Oppy’s key point is that positing God as one more ‘billiard ball’ in the sequence of causes studied by science yields no explanatory advantage. Surely he is right about this. As long as God is considered as one more billiard ball, we are better off with a natural billiard ball than a supernatural one. In my view, insofar as O’Connor is considering God as a cause among causes (and he seems to be), Oppy’s critique is devastating.
However, the point that there is no explanatory advantage to positing God as one more billiard ball was already recognized by classical theistic metaphysians such as Aquinas and Leibniz. This is, after all, precisely the point of the traditional distinction between primary and secondary causation: God is not a cause among causes, but rather stands outside the secondary causal sequence and makes that sequence, rather than another, actual. As has long been recognized, this is consistent with the sequence of secondary causes being either finite or infinite, for even if there was an infinite sequence, we could ask, ‘why that sequence and not another?’ and we could still answer, ‘because God so chose.’
Oppy will quite rightly respond that it is incumbent on the theist to render this notion of ‘primary causation’ intelligible. However, recent work in analytic metaphysics on ‘grounding’ and ‘building relations’ (as Karen Bennett calls them) suggests that this can be done. In brief, it is now (again) recognized that there are a plurality of metaphysical relations that can ground explanation. The theist wants to say that this causal sequence exists because God chose it. This ‘because’ need not signify the same causal relation by which (literal or metaphorical) billiard balls are regularly related to one another. Just exactly what the theist should take primary causation to be, and exactly how it should be seen as relating to other grounding or building relations, is an interesting topic for further research. But the long and short of it is, even if not much can be said about exactly what primary causation is, if primary causation is a species of building relation, and we understand building relations in general, and we are independently committed to a plurality of them, then it seems to me that the ideological cost of believing in primary causation is not so great as to offset the benefit of explaining something the naturalist doesn’t even try to explain: namely, why this causal sequence is actual.
Now, that theism can overcome this ideological cost is not enough to show that it is preferable, for this is not the only cost of theism. God is supposed to be a really (fundamentally) existing entity, and hence positing a God is itself an ontological cost. If God is a sui generis entity in a fairly strong sense (as opposed to, for instance, to literally being a mind), then there is also a significant ideological cost here. One alternative is to posit some necessary laws of nature (or something like that) to make the causal sequence go the way it does, but if one uses the word ‘God’ in such a way that ‘impersonal God’ is not a contradiction in terms, then this sounds like an impersonal God. Let’s set that aside. There’s a more basic issue to concern us. One way or another, we’re paying a lot to get an explanation of why this causal sequence is actual. If, as Shieva Kleinschmidt argues in the very next chapter, the Principle of Sufficient Reason is false and explanatory comprehensiveness is merely one theoretical virtue among many, then perhaps the cost is greater than we should be willing to bear. More on this next time.
(Cross-posted at blog.kennypearce.net.)