MIND, COSMOLOGY, AND SUFFICIENT REASON
A VINDICATION OF RATIONAL THEISM
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James F. Sennett
McNeese State University
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ABSTRACT
This paper examines the differing attitudes of theists and naturalists toward what has been called the "Principle of Sufficient Reason" (PSR): the metaphysical assumption that every event must have a sufficient reason for its occurrence. I examine the role of PSR in naturalistic and theistic approaches to two problems in the philosophy of mind: the dualism/materialism debate and the analysis of free will. I then compare these approaches to naturalistic and theistic approaches to current debates over the Cosmological Argument. I show that the theistic commitment regarding PSR is consistent across these arenas of debate, while the naturalistic commitment to PSR fluctuates and even contradicts itself. It is my conclusion that the theistic approach to these issues is more rational than the naturalistic approach, since the latter, unlike the former, involves an unjustified shift in attitude toward PSR.
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But nothing can be reduced from potentiality to actuality, except by something in a state of actuality.
--St. Thomas Aquinas
Nothing comes from nothing/Nothing ever could.
--Rogers and Hammerstein
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1. Introduction
This paper examines the differing attitudes of theists and naturalists toward what has been called the "Principle of Sufficient Reason" (PSR): the metaphysical assumption that every event must have a sufficient reason for its occurrence. I will examine the role of PSR in naturalistic and theistic approaches to two venerable problems in the philosophy of mind: the dualism/materialism debate and the analysis of free will. I will then compare these approaches to naturalistic and theistic approaches to current debates over the Cosmological Argument. I will show that the theistic commitment regarding PSR is consistent across these arenas of debate, while the naturalistic commitment to PSR fluctuates and even contradicts itself. It is my conclusion that the theistic approach to these issues is more rational than the naturalistic approach, since the latter, unlike the former, involves an unjustified shift in attitude toward PSR.
One of the most bizarre twists (from a philosophical standpoint) in the above-mentioned debates over the Cosmological Argument is the degree to which PSR has come under attack by those wishing to refute the argument. I label this development "bizarre" because PSR, or something near enough to it to ramrod most versions of the argument through, seems, in other philosophical contexts, to be a sine qua non of philosophical and scientific inquiry. That all events have sufficient reasons why they, and no other events, occurred when they did strikes one as the unquestioned assumption that drives continued inquiry even in the face of seemingly recalcitrant obstacles to discovery. (In fact, as I will show below, it is actually a stronger claim, entailing but not entailed by PSR, that contributes to this drive.)
As I tell my Introduction to Philosophy students, if your mechanic told you that she could not find the reason for the noise your car was making, you would have little trouble accepting her surrender (though you might then be in the market for a new mechanic!). But if she told you that there was no reason for the noise, that the car could be in exactly the same shape it is in now and the noise not occur, you would not accept that claim. You would think of her not simply as an incompetent mechanic, but as a mentally challenged buffoon. Yet when such a claim is made regarding the beginning of all physical processes, it is heralded as a serious and important philosophical treatise. That this move is suspicious is prima facie obvious. That such obviousness persists on examination is part of what this paper intends to show. (Of course, quantum mechanical considerations throw a conceptual monkey wrench into these musings, and introduce complications directly relevant to the issues at stake in the Cosmological Argument debates. I will have much to say regarding these considerations later in the paper.) Before beginning, I need to define several key concepts for the purposes of my argument. First, I consider any metaphysical view a physicalist one if it has the following implications: (i) every event with observable effects in the natural world is completely describable in physical terms; and (ii) every such event has only physical events in its causal history. So construed, physicalism does not entail that there are no non-physical objects or events. But it does entail that no non-physical objects or events have any causal influence on the physical world. (So the classical formulations of parallelism and epiphenomenalism could be physicalist positions.)
Second, I consider any theory of mind to be materialist if it entails that full descriptions of mental phenomena require no reference to any non-physical events.1 Note that mind/body materialism is consistent with the falsity of physicalism. It requires only that there be no non-physical events effective upon mental phenomena -- not natural phenomena in general. Physicalism, on the other hand, entails materialism (given that there are any mental phenomena at all). It will be important to remember that I am not using the terms 'physicalism' and 'materialism' as synonyms, although they are so used in some contexts. 'Materialism', as I employ it, picks out strictly a type of theory in the philosophy of mind, while 'physicalism' picks out a type of general ontological theory.
Third, I consider any theory of freedom compatibilist if it entails that every free action has a determinate physical cause. All three elements of this description are critical. Compatibilism as I construe it sees free actions as caused, just like any other events in the natural world. They are not sui generis events that require some other kind of explanation (i.e., non-causal reasons) for their occurrence. Furthermore, their causal explanation is determinate. Given the causal history, there is no alternative to the action's occurring. Finally (an most importantly, for my purposes), the determinate cause is fully physical. In other words, the causal history plus the laws of nature entail the event's occurring. Its causal history makes reference to no non-physical events or objects.2
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2. Physicalism and the Philosophy of Mind
Contemporary analytic philosophy of mind is rife with physicalism. And physicalism is most often understood to be in direct conflict with two classical positions in the philosophy of mind: interactive dualism in the mind/body problem and libertarianism in the free will/determinism debate. If interactive dualism is true, then mental events, many of which have observable effects in the natural world, satisfy neither of the above conditions: they are not fully describable in physical terms, neither do they have only physical events in their causal histories. The case is not quite so clear-cut with libertarianism. However, there seems at least prima facie to be some type of major conflict. After all, if libertarianism is true, then free actions are such that their causal history makes reference to an agent or to reasons in ways that seem to defy physicalist reduction.
It is no wonder, then, that the current bent toward physicalism has led almost all contemporary analytic philosophers away from dualism3 and libertarianism and toward mind/body materialism and compatibilism. In fact, one suggesting a dualistic or libertarian approach may well find herself greeted with the same incredulity as she would were she to suggest a geocentric model for the solar system or an alchemy or phlogiston approach to chemistry. However, since "get real" has never been a sufficient philosophical retort, it behooves us here to ask how an attitude of such wholesale dismissal came to be, and on what grounds it can be considered justified.
One point seems crystal clear and unarguable. Neither dualism nor libertarianism has been dismissed because it has fallen victim to any once-and-for-all philosophical refutation. The removal of these theories from polite metaphysical company has been more gradual, and a good deal more insidious. They have, so to speak, simply fallen out of fashion. The combination of semi-plausible materialist and compatibilist theories and an empiricist bent that worships at the altar of Ockham's razor have undoubtedly contributed to this shift in attitude.
However, debates among physicalists regarding the correct theories of mind and freedom are as heated and unsettled as any in philosophy. There is nothing like a consensus view in either field, so a claim that dualism and libertarianism are not needed, that the philosophical issues can be resolved without them, lacks any real bite. Furthermore, any philosopher with much dialectical flight time logged has ceased long ago to be impressed by points based solely on an appeal to Ockham's razor. It is a weapon wielded with tenacity when it serves one's present purposes and conveniently forgotten or dismissed as so much empty rhetoric when it aids one's interlocutor. So we must look further for justification for the abandonment of dualism and libertarianism in favor of materialism and compatibilism.
It is often charged that dualism and libertarianism "collapse under the weight of their own implausibility," or some such allegation. But it is hard to determine exactly what such an accusation comes to. If it amounts simply to the claim that no dualist or libertarian theory has been proposed that wins the approval of the philosophical community in general, then materialism and compatibilism (together with virtually every significant philosophical theory of the post Renaissance period) likewise collapse. If it is to be read as the claim that the theories are open to obvious refutation, then we must ask where such refutations are. If it is best construed as the view that there are better theories to be had, then we must ask both what those theories are and how one defends the claim that they are better. (As we have seen, there are none that could appeal to general acceptance in the community -- even if we were to accept that such would be evidence that it is better.) Finally, if we are to understand the charge as saying that dualism and libertarianism are to be rejected because they conflict with physicalism, then we are free simply to reply "so much the worse for physicalism," and the ball is back in the naturalist's court.
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3. PSR and the Philosophy of Mind
One might be tempted to think that materialism and compatibilism could be defended along empirical lines. But it is extremely difficult to specify what form such support might take. It certainly could not be straightforward inductive generalization. One could not argue for materialism, for example, as follows: "All mental phenomena examined so far have been found to have full physical descriptions; therefore all mental phenomena have full physical descriptions." Even if the inference here were a strong one -- a dubious claim at best -- the argument would still suffer from the deplorable flaw that its premise is patently false. So also with compatibilism. One could not simply drag out instance after instance of free action for which determinate physical causal explanation has been provided. The storehouse of such examples is quite deplete. Both analytic and empirical research in these areas is woefully lacking. Indeed, it is even unclear exactly what empirical evidence that such events have full physical causal explanation would look like.
But perhaps the empirical evidence should be viewed along more sophisticated inductive lines. Perhaps some concomitant variations case could be made. After all, neuroscience, psychology, cognitive science, and related disciplines do seem to give us ample evidence that there is very close correlation between brain activity and mental activity. One might argue that the more we learn about the brain, its stimuli, and its outputs, the more we are able to understand, predict, and explain mental phenomena. Such correlate increases in understanding surely provide strong evidence that, were we to know everything about the former, we would know all there is to know about the latter. And this, in turn, is good inductive evidence that mental phenomena just are physical phenomena.
This argument certainly holds more promise than the rather naive generalization argument offered before. However, it is far from convincing. In the first place, any dualist worth his salt will be quick to point out that there are any number of dimensions to mental phenomena for which there seems little hope of providing physical explanation. But more important is the problem that, to date, the amount of research done compared to the amount to be done is so infinitesimally paltry that any such monumental conclusions are certainly so far forth quite premature. There may well come a time when such an argument gains feasibility, but that time is well in the future, even if such is a physical likelihood or possibility. Certainly at present there exists nothing like the kind of correlative evidence needed to support so sweeping a claim.
And, besides, all of this is really beside the point. Research programmes in neurophysiology, cognitive science, and the like have not brought about the contemporary commitment to physicalist theories and the demise of dualism and libertarianism. Rather, such endeavors were by and large motivated by such commitments. It is because science and philosophy have come to the conviction over the past couple of centuries that mental life could be successfully described and studied in scientific terms that research has turned so single mindedly to such tasks. Not only is a priori commitment to physicalism required to make a good argument for materialism and compatibilism (since empirical evidence for them is sorely lacking); as a matter of fact it is clear that such commitment really is the explanation for how wholesale commitments to these views came about. In short, this a priori belief in physicalism provides not only the justificatory, but the genetic story for the current materialist and compatibilist cults in the philosophy of mind.
But here we must admit a conceptual truism. Physicalism all by itself is not enough to justify materialism or compatibilism. This is most easily seen in the fact that there are coherent antirealist positions in both debates. Eliminativists argue that no successful physicalist story of mental phenomena is forthcoming, though they are certainly as committed to physicalism as any good identity theorist or functionalist. And so-called "hard determinists," while holding with compatibilists to a thoroughgoing physicalism, nonetheless side with libertarians that the idea of compatibilist freedom is incoherent.
But even from a mental realist standpoint, physicalism is quite consistent with the claim that lots and lots of events have no causal explanation whatsoever, let alone determinate physical causal explanation. Consequently, there is nothing about physicalism per se that requires or even suggests that mental phenomena have any causal matrices to be uncovered. The most natural way to cover this gap (and, I would insist, the way that it is in fact covered for most physicalists) is by conjoining physicalism with some form of PSR. If PSR is true, then mental events and free actions must have full explanations for why they, rather than any other events, occurred. If physicalism is also true, those full explanations must come in the form of determinate causal explanations. So physicalism conjoined with PSR (and mental realism) gives us a good a priori argument for materialism and compatibilism.
Some may insist that physicalists have a way to justify these approaches without appeal to PSR. Perhaps what motivates them to seeking purely physicalist, causally closed accounts of mind and freedom is what we might call the Humean dilemma. All events in the physical world are either sufficiently causally determined or they are random (a premise consistent with the falsehood of PSR). Furthermore, nothing that is random can be thought of as under the control of any agent. However, since many mental events and all free actions are clearly under the control of the agents experiencing or producing them, it follows deductively that such events are not random and therefore fully causally determined.
But here we must ask why mental events and "free" actions are not simply dismissed as random events without sufficient physical causation. If such is a physical possibility (and it must be if the above argument is to escape commitment to PSR), then what makes us so sure that mental events and free actions don't fit into it? If the naturalist is to avoid a simple and unconvincing appeal to intuition, the answer has to be something along these lines: mental events and free actions display far too much order, structure, and predictability to be random and without explanation. But this, of course, is a very dangerous path for a naturalist to trod, since it leads inexorably into the teeth of the Teleological Argument. If order, structure, and predictability are evidence of a non-random, sufficient explanation, then the universe as a whole is providing evidence every day that it is neither random nor without explanation.
In fact, appeal to order, structure, and predictability in this case can be seen to aid the Cosmological Argument as well. After all, we do not observe the mental events or even the free actions (thought of, as Campbell suggests, as "inner" actions -- decisions or choices) themselves, but rather the effects in the physical world that such events have. So we do not infer from the order, structure and predictability of the mental events themselves that those events are not random but sufficiently explainable, but rather we infer that those events are so explainable from the order, structure, and predictability of their effectual consequences. So, if the order, structure, and predictability of the effectual consequences of a given class of events E are convincing evidence that the members of E are not random but sufficiently caused or explained, then the order, structure and predictability of the present state of the universe are convincing evidence that the Big Bang was not random but sufficiently caused and explained. This conclusion, by the naturalist's own admission, favors theism over naturalism. So this attempt to justify materialism and compatibilism without appeal to PSR is counterproductive for the naturalist. He'd best not go there.
But where else is there for him to go? There seems to be no other way to justify the claim that mental events are real and sufficiently caused by physical processes, not random, than by appeal either to the order, etc., of the consequences of mental events, or by appeal to something like PSR. Since the former leads to a serious conflict in the naturalist's position, the only place left for the naturalist is PSR.
So there are two crucial elements in the naturalist's embracing of materialism and compatibilism: physicalism and PSR. Together these doctrines entail an even stronger form of PSR, which I will call the Physical Causation Closure Principle (PCC): that all events have sufficient physical causal explanations. PCC is stronger than PSR in at least one very important way for our purposes. It specifies that the sufficient reason for any event's occurrence is a physical causal explanation. In other words, any event can be fully explained by appeal solely to physical events. PSR itself carries no such requirement. It is perfectly consistent with the claim that the sufficient reason for some events makes appeal to non-physical events, or even to agents. But when conjoined with physicalism such possibilities are removed, and the only way for an event to be sufficiently explained is by appeal to physical events.
Note that dualism is inconsistent only with PCC, not PSR. It is perfectly consistent with dualism that mental events have sufficient reasons for their occurring rather than some alternate mental event or no event at all. The only proviso is that such reasons will make reference to at least some non-physical events (hence PCC is false). In fact, it would be a gross misrepresentation of the best of dualistic philosophy to suggest that it is committed to the falsehood of PSR. So, while materialism requires not only the truth of PSR but of PCC as well, dualism requires only the truth of PSR. And, of course, by far the most popular theistic approach to the mind/body problem has been a dualistic one, while naturalism is virtually committed to a materialistic view of mind. So while both theist and naturalist make use of PSR in their approaches, the naturalist employs, while the theist rejects, PCC.
So also libertarianism, while inconsistent with PCC, is nonetheless perfectly consistent with PSR. In fact, so-called agent causation theories are motivated, at least in part, by desires to satisfy the constraints of PSR within the libertarian framework. The relative lack of success of such theories to date does not detract from the fact that libertarians need not reject PSR, and are in fact often moved by it. And, as before, theism will often move its adherents to libertarianism, while naturalists who desire to maintain some coherent notion of free will find themselves pulled inextricably to compatibilism. In both cases, then, theists follow a lead spurred on by PSR but in direct opposition to physicalism or PCC, while naturalists find themselves committed not simply to PSR but to PCC as well.
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4. PSR and the Thomistic Cosmological Argument
I believe the above makes a good case for the claim that naturalists are committed to PSR (and, in fact, the stronger thesis PCC) if they are to provide adequate defenses of realist naturalistic approaches to the mind/body problem and the analysis of human freedom. However, naturalists seldom if ever appeal explicitly to PSR or any such principle in these approaches. By contrast, it is crystal clear that naturalists must deny PSR and do explicitly deny PSR in their attempts to avoid conclusions with theistic (or at least supernaturalistic) overtones in the debates over the Cosmological Argument.
It has become customary to speak of the Cosmological Argument as coming in two different forms or versions, which I will call the Thomistic Argument or the Contingency Argument, and the Kalam Argument or the First Cause Argument. The former argues that a necessary being must exist given that contingent beings exist, and is most famously represented in the first three of Aquinas's "Five Ways." The latter argues that there must be a temporal beginning to the universe, and that such beginning requires a necessary being. This form is borrowed primarily from the Arabic philosophers of the Medieval period (Kalam being the Arabic word that came to refer to the Arabic scholastic movement).4 It is telling that both versions of this argument have been attacked recently by naturalistic philosophers on the grounds that (i) the argument depends on PSR and (ii) there is either good reason to think PSR false or there is no good reason to think it is true.
William Rowe has presented an eloquent exposition and criticism of the Thomistic Argument, in which he demonstrates that this version actually employs two different (though compatible) conceptions of PSR.5 "We may state PSR, therefore, as the principle that there must be an explanation (a) of the existence of any being, and (b) of any positive fact whatever" (p. 26, emphasis his) Rowe then shows quite convincingly that both PSRa and PSRb must be true in order for the Thomistic Argument to be sound. His dismissal of the argument, then, is based on a rejection, albeit a modest one, of PSR in either form. This rejection is based on the claim that neither of the two most common ways to defend PSR is convincing. (So his rejection is not a charge that PSR is false, but only that there is no reason to think that it is true.)
First, some claim that PSR is intuitively true. That is, "if we fully understand and reflect on what is said by PSR we can see that it must be true." But, protests Rowe, "a number of very able philosophers fail to apprehend its truth, and some even claim that the principle is false." Second, others claim that PSR must be accepted as "a presupposition of reason." That is, PSR is "a basic assumption that rational people make, whether or not they reflect sufficiently to become aware of the assumption." Rowe responds, "The fact, if it is a fact, that all of us presuppose that every existing being and every positive fact has an explanation does not imply that no being exists, and no positive fact obtains, without an explanation. Nature is not bound to satisfy our presuppositions" (p. 27).
Rowe's attack on PSR is open to three criticisms relevant to the purposes of the present paper. First, it seems that Rowe's criticism of the second defense of PSR can be turned against his criticism of the first. He protests that believing a proposition doesn't make it so. Fair enough. But it follows then that the mere fact that "a number of very able philosophers" hold either that PSR cannot be known to be true or that it is false does not make it true or even likely that PSR is either false or not known to be true. After all, by Rowe's own admission, seeing PSR to be intuitively true requires proper understanding and reflection. And this may be more than simply pondering or even turning an educated philosophical eye toward it in examination. It is intuitively true that there is no set of all propositions (by Rowe's definition of intuitively true.) However, the "proper understanding and reflection" required to grasp this intuitive truth is quite tricky, and is such that many well versed philosophers may have never grasped it. I have never grasped the intuitive truth of Godel's incompleteness theorem -- neither have many quite able mathematicians and philosophers. Yet intuitively true it is nonetheless.
In fact, the whole thrust of the first sections of this paper can be seen as pointing out one way in which the naturalist can reflect to grasp the truth of PSR intuitively. If it is false, then the naturalist has no way to defend his physicalistic approaches to mind/body and free will/ determinism without throwing the door open for non-naturalism and theism. Therefore, the naturalist should be at least as convinced of PSR as he is of naturalism.
A second problem lies in Rowe's criticism of the claim that PSR is a presupposition of reason. Rowe never argues that PSR is not a presupposition of reason; only that, even if it is, this is no evidence that it is true. So let us, with Rowe's apparent permission, assume for a moment that PSR is a presupposition of reason. He defines such as "an assumption that rational people make, whether or not they reflect sufficiently to become aware of the assumption." I take this last clause to mean that a presupposition is something that can be (an perhaps most commonly is) assumed tacitly, i.e., without the conscious awareness of the person. How are we to understand this notion? It seems to me that the only way to argue that one tacitly assumes p is to show that one is committed to p -- that is, that one's beliefs or practices either entail p or require the truth of p to qualify as rational, justified, etc. So the only way I see to understand the notion of PSR as a presupposition of reason is that rational people qua rational people are committed to PSR.
Rowe claims that even if PSR is a presupposition of reason, this is no guarantee that it is true. Of this there can be no doubt. However, what does seem to follow is that no one can deny or even doubt PSR on pain of irrationality. So, insofar as the controversy over PSR is the only barrier to a successful Thomistic Argument (and Rowe does refute every objection to the argument he considers except this one), it follows that one cannot rationally reject the argument. That is, either one who understands the argument believes that there is a necessary being or such a one is being irrational. This is certainly not the conclusion Rowe was looking for.
In Rowe's defense I must point out that he is considering whether or not the Thomistic Argument succeeds as a piece of what we might call "Strong Natural Theology" (SNT). Natural Theology simpliciter has as its goal the construction of successful arguments for God's existence using only empirical or a priori premises. SNT would be the view that a Natural Theology argument is successful only if it can be shown to be sound. Now, Rowe is certainly correct to claim that PSR as a presupposition of reason does not show the Thomistic Argument to be sound. Nothing I have said suggests otherwise. However, consider the notion of "Modest Natural Theology" (MNT). MNT holds that a Natural Theology argument is successful if it shows that any rational person who properly understands and reflects upon the argument would be justified in accepting its conclusion and would be irrational in withholding judgment on or rejecting the conclusion. If PSR is a presupposition of reason (and there are no other problems with the argument), then the Thomistic Argument is a successful piece of MNT. And any contemporary theistic philosopher would be more than satisfied with this conclusion.
This all suggests my third criticism of Rowe, and that is that I think the proper way to think of PSR is as a combination of the two he suggests: intuition and presupposition. I would make the claim that it is intuitively true that PSR is a presupposition of reason -- at least in a world so immersed in scientific discovery, so awash in rational discourse and action, so aware of psychological, sociological, and historical developments. In a world in which we won't let our auto mechanics get by with "there's no reason," we can't let ourselves get by with it either.
Continued..... |
