Natural theology, natural science, and the philosophy of nature

Physicist Robert Oerter has added some further installments to his series of posts on my book The Last Superstition, including a reply to some of my criticisms of his criticisms of the book.  I will respond to his latest remarks in a forthcoming post, but before doing so it seemed to me that it would be useful to make some general remarks about certain misunderstandings that have not only cropped up in my exchange with Oerter and in the combox discussions it has generated, but which frequently arise in disputes about natural theology (and, for that matter, in disputes about natural law ethics and about the immateriality and immortality of the soul).  In particular, they tend to arise in disputes about what we might call classicalnatural theology -- natural theology grounded in philosophical premises deriving from the Aristotelian, Neo-Platonic, and/or Scholastic traditions.

To understand the arguments of classical natural theology -- arguments like Aquinas’s Five Ways, for example -- you need to understand the difference between empirical science on the one hand and metaphysics and the philosophy of nature on the other.  And you need to understand how the attitudes that classical philosophers (Aristotelians, Neo-Platonists, Thomists and other Scholastics) take toward these three fields of study differs from the attitudes common among modern philosophers (whether early modern philosophers like Descartes, Hobbes, Locke, Leibniz, Hume, Kant, and Co., or the average contemporary academic philosopher, who has -- often unreflectively -- inherited his basic philosophical assumptions from the early moderns).  For the arguments in question are grounded in the philosophy of nature (and in some cases in metaphysics) and not in natural science; and they are grounded in a classical rather than modern philosophical understanding of the three fields and their relationship to one another.  (I addressed this issue in a recent lecture which you can watch via YouTube.  What follows is some conceptual and historical background to what I said there.)

What is the philosophy of nature?

Metaphysics, as traditionally defined in Aristotelian philosophy, is “the science of being qua being.”  What that means is that it is not concerned merely with this or that kind of being, but with being as such, with what is true of anything whatsoever that does have or could have being.  Thus it is concerned with questions like:  What is it to be a substance?  What is an essence?  What is it to exist?  What is it to have quantity?  What is a quality?  What are universals and what is their relationship to particulars?  And so forth.  

Empirical science, as it is typically understood in modern times, studies material reality by developing quantitative models and testing them by observation and experiment.  That, at any rate, is the paradigm, which is why physics -- with its mathematical formulae, rigorous predictions and technological applications, and discovery of strict laws -- is commonly regarded as the gold standard of science.  

The philosophy of nature is a middle ground field of study, lying between metaphysics and empirical science.  Unlike metaphysics, it is not concerned with being as such, but with changeable, empirical reality in particular.  But neither is it concerned merely with the specific natures of the changeable, empirical things that happen to exist.  It is rather concerned with what must be true of anyworld of changeable, empirical things of the sort we might have scientific knowledge of, whatever their specific natures and thus whatever turn out to be the specific laws in terms of which they operate.  Nor is the philosophy of nature concerned merely with the quantitative aspects of material things, but with every aspect of their nature.  In Aristotelian philosophy of nature, these fundamental features of any possible empirical reality (or at least any sort we might have scientific knowledge of) include act and potency, substantial form and prime matter, efficient and final causality, and so forth.  (That is not to say that some of these concepts don’t also have broader metaphysical significance.  But the philosophy of nature approaches them from the point of view of the role they play in making sense of the empirical world, specifically.)

Now one immediate source of potential confusion is the fact that the terms in question are not used by all writers on these subjects in quite this way.  Contemporary analytic philosophers tend to use the term “metaphysics” in a broader sense that includes not only what Aristotelian-Scholastic philosophers would think of as “metaphysics,” but also questions that fall under the philosophy of nature.  For example, in contemporary analytic metaphysics one finds discussion of whether fundamental physical entities have essences in virtue of which they behave in the ways they characteristically do, whether there are categorical as well as dispositional properties in nature, whether dispositions posses a kind of “physical intentionality” or “natural intentionality” insofar as they are directed toward their typical manifestations, and so forth.  This is (even if not all the metaphysicians in question realize it) more or less a revival of Aristotelian and Scholastic notions like substantial form, act and potency, final causality, and the like.  And it often arises in contexts where what is at issue is how to interpret the results of modern physics.  Hence it really amounts to a revival of the philosophy of nature -- and is sometimes presented as such -- but is nevertheless commonly regarded as part of “metaphysics.”

Aristotelian writers, meanwhile, sometimes use terms like “science” and “physics” in a way that includes theses in the philosophy of nature.  This reflects the older, broader Aristotelian understanding of what it is to be a “science” and of what is included in the domain of “physics,” and is a perfectly defensible usage of the terms.  But it is so different from the way most people use the terms these days that it seems to me that clarity is better served by following the practice of more recent Aristotelian and Scholastic writers of letting “science” and “physics” retain more or less their current meanings, and then using “philosophy of nature” to cover the sorts of topics I cited as characteristic of that field of study.  

A further complicating factor is that much of what falls under the label “science” these days doesn’t really fit the physics paradigm, whatever people like Alex Rosenberg think.  Indeed, even some of what physicists themselves say is really philosophy rather than physics.  Thus, when physicists pronounce upon the nature of physical law, or causality, or the role of the observer in physical systems, they are really (in part) doing philosophy of nature, metaphysics, or epistemology rather than physics.  And when some contemporary scientists and philosophers of science suggest an “emergentist” or “non-reductive physicalist” interpretation of certain chemical, biological, or psychological phenomena, they are really rediscovering (albeit in an often piecemeal or inchoate way) Aristotelian notions like substantial form, immanent final causality, etc. -- and in the process rediscovering that natural phenomena cannot be exhaustively described in the quantitative terms characteristic of physics, but require for their analysis the conceptual tools provided by the philosophy of nature.  

Now if we nevertheless insist on counting these sorts of claims as part of “science,” then we are in effect returning to something like the older, broader Aristotelian sense of the term -- a sense that includes the sorts of theses I’ve characterized as part of the philosophy of nature.  If instead we go along with the modern conceit that something falls short of “real” science to the extent that it fails to conform to the mathematical and predictive techniques of physics and/or fails to be reducible to what physics tells us exists, then (the Aristotelian will argue) this entails that “science,” so defined, captures only certain aspects of material reality, and philosophy of nature captures the rest.

In any event, it is, as I have said, in premises drawn from the philosophy of nature (and in some cases in premises drawn from metaphysics), rather than in premises derived from science in the modern narrow sense, that the arguments of classical natural theology are grounded.  (The same thing is true, at least to a large extent, of arguments in classical natural law theory and in classical arguments regarding the existence and nature of the soul.  For example, Thomistic natural law theory is grounded in the idea that human beings have an essence in the sense of having an immanent nature or substantial form.  Hence, while discovering the details of human nature is something to which empirical science is relevant, the question of whether we have such a nature in the first place is not a question for empirical science, but a question for the philosophy of nature.  By the same token, since for the Aristotelian-Thomistic tradition, the human soul is the substantial form of a human being, and intellect and will are powers inherent in anything having such a form, human action -- and thus questions about free will -- can only properly be understood in terms of concepts derived from philosophy of nature.  And so forth.)

Classical versus modern philosophy

Early modern philosophy was defined more than anything else by its rejection of the Aristotelian-Scholastic apparatus of act and potency, substantial form and prime matter, final causality, etc. -- that is to say, by its rejection of the Aristotelian-Scholastic philosophy of nature.  Now in one sense, what the early moderns put in its place was an alternative, “mechanistic” philosophy of nature, central to which was the insistence that there is in the material world nothing like substantial forms or immanent natures and nothing like immanent or “built in” teleology.  But in another sense, precisely because this alternative philosophy of nature was essentially negative, defined only by the Aristotelian ideas it rejected rather than in terms of any positive content (or at least was entirely negative after earlier aspects of mechanism like push-pull causation were abandoned), the effect was that philosophy of nature as a field of study largely disappeared.  Empirical science came to be seen as giving us the wholetruth about the material world rather than only the quantifiable aspects of material world.

Now the story is in fact more complicated than this.  Despite his hostility to Scholasticism, Descartes’ work is permeated with Scholastic ideas (albeit they are put to anti-Scholastic use).  Writers like Locke attempted to formulate, in a manner consistent with the new “mechanical philosophy,” something like the older Aristotelian-Scholastic idea that material objects have inherent powers.  Newton and others thought that extrinsic final causes -- teleology imposed on the world entirely from outside, by God -- were necessary for a complete account of the natural world.  But gradually these ghosts of the older Scholastic framework disappeared and the view that the material world as described by physics just is the material world full stop came to prevail.  There have, of course, always been dissenters who pointed out that this cannot be right -- that the abstract mathematical structure described by physics cannot be the whole story, since there needs to be some concrete reality to have this structure.  Idealists, process philosophers, and neutral monists would make diverse suggestions about the nature of this underlying reality -- seeking, in effect, a new philosophy of nature that would allow them to resist reductionism without returning to Aristotelianism.  And Neo-Scholastics would, of course, continue to uphold the Aristotelian position.  But materialists and their Cartesian opponents alike would come to treat natural science as if it gave us an exhaustive description of material reality.  And since materialism and Cartesianism came to seem the main alternatives in general metaphysics, the philosophy of nature as a field of study largely dropped off the radar screen.  

As this middle ground field of study virtually disappeared, metaphysics on the one hand and natural science on the other came to seem the only avenues of investigation of reality.  And metaphysics no less than science was transformed as a consequence of the abandonment of the Aristotelian-Scholastic philosophy of nature.  For Aristotelian metaphysics itself can be seen to be an outgrowth of the philosophy of nature.  Consider the theory of act and potency.  It originated as a response to the view of Parmenides and Zeno that change and multiplicity are illusions.  It is thus central to the Aristotelian account of how it is possible for there to be a world of diverse empirical, changing things susceptible of scientific study.  But these notions end up having a completely general application.  Being, the core notion of metaphysics, is inseparable from the notion of act or actuality.  Though metaphysics takes us well beyond the natural world, then, its concepts have a foundation in our empirical knowledge of that world -- to be sure, not necessarily in the knowledge of the specifics of the empirical world that natural science gives us, but in the knowledge of what must be true of any empirical world in general, which the philosophy of nature gives us.

But when this middle ground discipline was effectively abandoned, metaphysics could no longer be given such a foundation.  Moreover, general epistemology was bound to be transformed as well, since the epistemology of the Scholastics had also been grounded in Aristotelian concepts.  Empiricism and rationalism would fill the void, and radically alter not only epistemology, but metaphysics as well.  Now for the Aristotelian no less than for the empiricist, all of our concepts and all knowledge must ultimately derive from experience.  But for the Aristotelian, concepts are irreducible to images or phantasms, so that strictly intellectual activity, though grounded in sensation and imagination, ultimately outstripssensation and imagination.  (To take a simple example, our concept of triangularityhas a universality and determinacy that mental images and sensations cannot have.)  The modern empiricists, by contrast, denied that there is any difference in kind between intellectual activity on the one hand and sensation and imagination on the other.  (Hence to have the concept of triangularity came to be seen by them as a matter of associating a mental image of a triangle with the general term “triangle.”)  The history of empiricism from Locke to Hume is a history of the gradual drawing out of the implications of this conflation -- namely complete skepticism about the very possibility of metaphysical knowledge, or indeed any knowledge at all, since this would require the having of concepts that outstrip one’s immediate sensations and mental images.  (This remains true even if we interpret Hume as a kind of “skeptical realist.”  Realism might for Hume be part of common life, but it still has in his view no rationalfoundation, and its hold over us rests on a kind of animal faith.)  

Now the rationalists could see that intellectual activity cannot be reduced to sensation and imagination and that we have all sorts of concepts that cannot be accounted for on a modern empiricist epistemology.  But rather than grounding these concepts in empirical reality by reaffirming the older, richer Aristotelian understanding of the role of experience in concept formation, the rationalists divorced our key metaphysical concepts from empirical reality altogether.  Such notions were held to be a priori or even “innate.”  When the doctrine of innate ideas and the notion of a priori knowledge came to seem problematic, metaphysics came in turn to seem grounded in mere “conceptual analysis” or even in contingent linguistic usage.  Key metaphysical theses were thereby transformed and ultimately deflated.  For example, the Aristotelian-Scholastic principle of causality -- which is intended as a claim about objective reality -- was transformed into the rationalist “principle of sufficient reason” -- a so-called “law of thought,” in effect a description of our explanatory practices.  And to the extent that metaphysics came to seem little more than conceptual analysis or wordplay with no necessary connection to mind-independent or language-independent reality, the principle of sufficient reason came to seem lacking in any necessary application to the objective world -- an ungrounded insistence that the world meet our explanatory demands.  Kant’s critique of metaphysics was, naturally, the sequel.

Natural theology was also radically transformed as a result of these developments.  Since a thoroughgoing empiricism ultimately takes everything down with it -- natural science no less than metaphysics -- the empiricist tradition has tried to pull back from the Humean brink and modify its position in a way that will make room at least for science.  Accordingly, the broadly empiricist approach to natural theology has been to transform it into a kind of scientific theorizing, making of God a “hypothesis” “postulated” as the “best explanation” of this or that natural phenomenon -- Paley’s design argument being the best-known instance of this kind of “natural theology.”  Rationalists, by contrast, grounded natural theology in metaphysical rather than scientific premises, but where the metaphysical premises in question are purportedly a priori theses like the principle of sufficient reason -- Leibniz’s version of the cosmological argument being a well-known instance of this kind of natural theology.  Kant’s critique of natural theology, an extension of his critique of metaphysics, lay just around the corner.  

Most contemporary commentators on the issues we’re discussing, including most academic philosophers, think entirely inside the box constructed by the early moderns.  If you say that metaphysics provides knowledge that natural science cannot give us, they will assume that you must believe that such knowledge has no empirical foundation but derives instead from something called “conceptual analysis.”  If you say that there are solid arguments for the existence of God, they will assume that you must be committed either to something like Paley’s design argument or to some Leibnizian sort of cosmological or ontological argument.  If you respond that you are talking instead about (say) Aquinas’s Five Ways, they will assume that Aquinas was just giving arguments of the sort Paley, Leibniz, et al. gave.  And if you answer that the sorts of arguments you have in mind are grounded instead in the philosophy of nature, most of them will have no idea what you are talking about.  They simply do not realize how radical are the differences between classical and modern authors, and how contingent and open to challenge are the assumptions made by the latter.

Some common misunderstandings 

As I have indicated, ignorance of the distinction between natural science, metaphysics, and the philosophy of nature, and of the differences between the classical and modern conceptions of these three fields of study, underlies a number of common misconceptions about the arguments of classical natural theology.  Here are some of them:

1. Confusing questions in philosophy of nature with questions of empirical science

When Aristotelians maintain that any actualized potential must be actualized by something already actual (a version of the principle of causality), or that there are substantial forms, or that there are final causes immanent to material processes, they are not trying to answer the sorts of questions empirical science (in the modern, narrow sense discussed above) is trying to answer.  Empirical science seeks to uncover the physical causes that happento exist, or the chemical structure of the material substances that happen to exist, or what have you.  The philosophy of nature is concerned with deeper questions -- for example, with what has to be true if there is to be any causality at all, or any material substances at all.  

Hence, when the Aristotelian says (for example) that natural objects must have substantial forms, he is not trying to give an explanation of the sort that the modern chemist is giving.  He is not claiming that we can say everything we need to know about opium simply by noting that whatever it does it does by virtue of its substantial form, and that no further chemical analysis is needed.  Rather, he is saying that, whatever the specific chemical details of opium (or water, or lead, or whatever) turn out to be, if these really are natural substances about which we can have scientific knowledge, then there must be some intrinsic principle that grounds the properties that chemistry uncovers and that gives them the regularity that chemistry shows them to have.  That is to say, it cannot be that a tendency toward such-and-such effects is to be found only in this or that sample of opium, but must derive from opium as such, from something common to any instance of opium; it cannot be that opium’s typical behavior derives from something extrinsic to it, but must be grounded in an inherent source; if it has causal properties that are irreducible to those of its parts, then there is a sense in which opium itself is irreducible to its parts; and so forth.  Naturally we still have to do chemical analysis in order to discover the specific means by which opium brings about its characteristic effects.  The Aristotelian does not deny this because he is not making a claim that is in competition with chemistry.  He is rather approaching the phenomenon from a different and more fundamental level of analysis, and asking a different sort of question about it.  (This is one reason Moliere-style “dormitive virtue” objections to substantial forms are puerile.  I have discussed that objection in more detail in The Last Superstition and Aquinas.)  

Thus, to raise considerations from physics, chemistry, biology, etc. as if they cast doubt on arguments like Aquinas’s Five Ways is simply to make a fundamental category mistake.  For such arguments are not addressing the same sorts of questions addressed by natural science in the first place, but rest instead on premises derived from the philosophy of nature.  Nor is the point merely that empirical science is different fromthe philosophy of nature.  Natural science is less comprehensive and fundamental than the philosophy of nature.  Physics in particular confines itself to those aspects of material reality susceptible of rigorous prediction and control, and thus susceptible of mathematical modeling.  It deals with abstractions from concrete reality, not concrete reality itself.  It does not tell us anything about the deeper nature of the substances and processes that bear the mathematically definable properties it identifies.  But that deeper nature is precisely what the philosophy of nature is concerned with.  

This, as I have emphasized before, is the deep reason why considerations drawn from Newtonian mechanics or quantum theory simply do nothing to undermine arguments like Aquinas’s First Way, contrary to what Oerter and others suppose.  For physics does not give us anything close to a complete description of material reality in the first place.  Hence, that physics makes no reference to some principle affirmed in Aristotelian philosophy of nature is neither here nor there.  You might as well say: “There’s good reason to think that the scissors cannot be in any of the kitchen drawers.  Therefore the scissors are nowhere in the house.”

No doubt some will object that this makes arguments like Aquinas’s “unfalsifiable” or otherwise arbitrarily immune to criticism.  This is like saying that someone who insists on looking for the scissors in the rest of the house and who refuses to draw conclusions from what can be found in the kitchen drawers alone has thereby made his position unfalsifiable.  Obviously such a person’s position is not unfalsifiable; rather, the range of evidence that may or may not falsify it is simply larger than is supposed by someone who is fixated on the drawers.  Similarly, nothing I have said entails that the arguments of classical natural theology are not subject to rational evaluation or criticism.  The claim is rather that the kind of rational evaluation and criticism to which they are subject is not the sort typical of empirical science.

2. Confusing nonessential illustrations with crucial empirical claims

A related error is the confusion of examples that are intended merely to illustrate philosophical points with purported empirical evidence for those points.  For example, expositions of Thomistic arguments for the existence of God often make use of examples like that of a hand which is moving a stick in order to move a stone.  One point of such examples is to introduce the idea of instrumental causality, where an instrumental cause is one whose causal power derives from something outside it, as the stick derives its power to move the stone from the hand.  Another point of such examples is to introduce the idea that God is cause of the world not merely in the temporal sense of having gotten the universe going at some point billions of years ago, but in the deeper sense of keeping the universe going at every moment, just as the stick’s movement of the stone persists only insofar as it is itself kept moving by the hand.  

Now when a physicist illustrates a point he is making by asking us to imagine what we might experience if we fell into a black hole or rode on a beam of light, no one thinks it a clever response to point out that photons are too small to sit on or that we would have been ripped apart by gravity long before we made it into the black hole.  Such “objections” would completely miss the point.  But it would similarly miss the point to insist that Aquinas is refuted by the fact that there is a very slight time lag between the motion of a stick and that of a stone it is pushing (as one hostile reader of this blog used to point out obsessively a few years back, as if it were a fatal objection).  For nothing in Aquinas’s argument rides on the question of whether the motion of a stick and that of the stone it is pushing are strictly simultaneous, any more than it rides on a hand’s really being a “first” or non-instrumental cause in the relevant sense (which it obviously is not since the hand itself is moved by the arm).  The example is intended merely as an illustrationto jog the reader’s understanding of abstract concepts like instrumental causality and conserving causality.  And as I have argued in several places, once the homely examples in question give us a grasp of these concepts, as well as of concepts like that of the actualization of a potency, we are on the way to seeing that even the sheer existence of a thing from moment to moment (never mind its local motion) requires a sustaining cause.  (For more on how properly to understand the causal claims made in arguments like the First Way, see this post, this post, and my ACPQ article “Existential Inertia and the Five Ways,” which you can read online by doing a Google search and clicking “Quick View” on about the fourth search result.)  

A somewhat different but related point is that the falsification of certain specific applications of theses derived from the philosophy of nature does not falsify the theses themselves.  For instance, Aristotle held that the local motion of an object like a stone has the earth, specifically, as its natural end or terminus.  He was wrong about that, but that does not show that there are no final causes or natural ends, any more than the falsification of phlogiston theory shows that combustion and rusting don’t have a chemical explanation.  That there are, in general, final causes, substantial forms, etc. in the natural order is something the Aristotelian argues we can know from philosophical analysis.  But the specific details of the nature or finality of this or that particular substance or process is something that requires careful empirical study, and claims about such details are open to empirical scientific challenge.  (Compare: Most naturalists would agree, on philosophical grounds, that there must in general be something like laws of nature if empirical science is to be possible at all.  But it doesn’t follow that every specific claimabout whether such-and-such is a law can be settled on general philosophical grounds, and it doesn’t follow that the falsification of such a claim shows that there are no laws after all.)

3. Reading modern philosophical assumptions back into classical writers

A third common error is to assume that the general philosophical assumptions underlying arguments in classical natural theology are the same as those made by modern writers.  As I have noted many times, reading Aquinas’s Fifth Way as if it were more or less the same as Paley’s design argument is a particularly egregious example of this error.  But it is also erroneous to assume that when classical writers like Aquinas talk about contingency and necessity, they are (like modern rationalist writers) appealing to what is “conceivable,” or to “possible worlds,” or to logical necessity.  And it is erroneous to assume that their versions of the cosmological argument rest on the “principle of sufficient reason,” if that is understood in Leibnizian rationalist fashion as a “law of thought.”  For the Scholastic principle of causality is a claim about objective realityitself -- not a claim about our explanatory practices, about how we do or even must think about objective reality (where the latter sort of claim opens modern cosmological arguments up to the Kantian critique).  

Again, classical writers would not accept the empiricist or rationalist assumptions that ultimately underlie modern arguments in natural theology -- assumptions that had their origin in the rejectionof the Aristotelian philosophy of nature in which arguments like those of Aquinas are grounded.

4. Radically oversimplifying the notion of “cause”

A fourth common error is a corollary of the others.  The Scholastic tradition had worked out a complex and sophisticated theory of causation.  For the Scholastics, following Aristotle, there are the four basic kinds of cause: formal, material, efficient, and final.  In the realm of efficient causes there is the principle of causality, the principle of proportionate causality, the principle of proper causality, distinctions between primary causes and secondary or instrumental causes, essentially ordered causes and accidentally ordered causes, total and partial causes, concurrent causes, sustaining causes, and so on.  Efficient causes were also taken to presuppose final causes, and final causes were in turn essentially connected to substantial forms (and thus to formal causes, which in turn were instantiated in matter and thus required material causes).  Now the moderns gradually chucked out almost all of this nuance -- which, despite its complexity, is really just a systematic articulation of common sense thinking about causation -- as they unpacked the implications of their anti-Aristotelian revolution.  By the time of Hume, little was left except the notion that causation involves some kind of necessary connection between temporally separated events, but where the “necessary connection” aspect was something for which it was hard to find an objective basis.  (See Kenneth Clatterbaugh’s The Causation Debate in Modern Philosophy 1637-1739 for a useful account of this gradual desiccation of the notion of cause.)  

In physics too the notion of cause was reduced more or less to the vanishing point -- to something like the law-like correlation between temporally separated factors A and B, where the causality of A per se is irrelevant and the law-like correlation is really all that matters.  Of course, that it is law-like seems to suggest some kind of inherent connection between A and B, but Humean empiricist arguments together with the replacement of law-like correlations with statistical ones effectively undermined the appearance of such a connection, so that causality itself seemed to recede like a will-o’-the-wisp.  

Now, if you start with the moderns’ desiccated notion of “cause” andbuy Hume’s empiricist presuppositions and/or the scientistic claim that physics gives us the whole story about material reality, then the causal claims made in arguments like Aquinas’s can seem shaky at best.  But there is (so the classical philosopher will argue) no good reasonto accept any of those presuppositions.  And in any event, merely to presuppose them simply begs the question against Aristotelian-Scholastic philosophy of nature, and thus begs the question against any argument grounded in that philosophy of nature, as Aquinas’s arguments are.

5. Begging the question in favor of scientism

New Atheist types tend to be very impatient with remarks of the sort I’ve been making.  They’ve absolutely fallen in love with the “Science has refuted religion” meme and don’t appreciate being shown how superficial and ill-informed it is.  As a consequence their tendency is to double down on the snark while just repeating yet again the very assertions that have been called into question.  “Science has refuted theism, and that’s that, and don’t bother me with all this philosophy BS, and nothing in this long-winded exercise in medieval nostalgia shows that your sky daddy exists and nyah nyah nyah I’m not listening anyway even though I find myself posting obsessively in your combox…”

Still, it is worth emphasizing for atheists of good will that it simply will not do to appeal to some further specific finding of modern science, or to the predictive and technological successes of science in general, or to what most contemporary academic philosophers happen to think.  All of this simply begs the question, for the reasons stated above.  And as I have argued many times (e.g. here, here, here, and here) there are in any event no good arguments for scientism and decisive arguments against it.

It also will not do to throw up one’s hands and retreat into agnosticism, declaring that even if science doesn’t answer every question, it is still the only intellectual enterprise worthy of attention since it is the only one that provides something close to definitive answers and consensus.  For one thing, this is like avoiding classes you know you won’t do well in and then appealing to your GPA as evidence of your superior intelligence.  As the esteemed Mike Flynn put it in a recent blog post:

[Francis Bacon’s] goal of “mastering and possessing” nature necessarily focused scientists on just those aspects of nature that could be predicted and controlled; and this required Descartes’ quantitative, mathematical approach.  Baconian science thus ensured that Nature would be “quantifiable, predictable, and controllable” by defining nature as quantifiable, predictable, and controllable. 

If you will allow to count as “scientific” only what is quantifiable, predictable, and controllable, then naturally -- and trivially -- science is going to be one long success story.  But this no more shows that the questions that fall through science’s methodological net are not worthy of attention than the fact that you’ve only taken courses you knew you would excel in shows that the other classes aren’t worth taking.

For another thing, the claim that questions susceptible of scientific investigation are the only ones worth investigating is itselfnot a scientific claim, but a philosophical claim, and thus one that requires a philosophical defense.  You cannot escape philosophy.  The only question is whether you will do it well or badly.  And if you pretend you are not doing it, or pretend that it is not worth doing, or refuse to familiarize yourself with its history and methods, you are going to do it badly.


Cinematic representation

What makes it the case that a picture of Grandma represents Grandma?  That it looks like her, you might say.  But that can’t be the right answer, or at least not the whole answer.  The picture might look like any of several people; still, it represents only Grandma.  Or it might not look much like her at all -- consider a bad drawing, or even a photograph taken at an odd angle or in unusual lighting or while the subject is wearing a very unusual expression -- yet still represent her.  Indeed, that resemblance of any sort is neither sufficient nor necessary for representation is about as settled a philosophical thesis as there is.  (The reasons are many.  An object might resemble all sorts of things without representing them.  Resemblance is a symmetrical relationship, but representation is not: If a certain picture resembles Grandma, Grandma also resembles the picture; but while the picture might represent Grandma, Grandma does not represent the picture.  There are many things we can represent in thought or language -- the absence of something, a certain point in time, conditional statements, disjunctions, conjunctions, etc. -- without these representations resembling their objects, either pictorially or in any other way.  And so forth.  Chapter 1 of Tim Crane’s The Mechanical Mind provides a useful discussion of the issue.)

Nevertheless, there are certain kinds of representation of which resemblance is an important component, even if it is not the whole story.  Movies provide some useful examples, the most obvious of which is the biopic.  Now, an attempt at perfect imitation of the subject of such a movie is neither necessary nor always desirable.  Patton would not have been as effective as it is had George C. Scott tried to capture the General’s somewhat nasal voice.  Still, verisimilitude can be very effective -- Meryl Streep’s portrayal of Margaret Thatcher has justly been praised.  And to fail to capture in at least a general and impressionistic way the appearance and mannerisms of the subject will make it impossible to suspend disbelief.  (Cliff Robertson as JFK, anyone?)

There are more complex and interesting ways in which resemblance plays (or does not play) a role in effective cinematic representation.  Consider the comic book flick, about which I’ve written before.  On the one hand, Edward Norton in The Incredible Hulkand Mark Ruffalo in The Avengers could plausibly portray the same character -- the Hulk’s alter ego Bruce Banner -- in what was in effect the same multi-part story, though the two actors do not much look like each other.  On the other hand, the CGI Hulk in the latter movie better represents the character precisely because its features were made to resemble Ruffalo’s.  (All of this works, perhaps, because we’ve got something like a Wittgensteinian “familyresemblance” between the various “players” -- Ruffalo facially resembles the CGI Hulk in The Avengers, who in other respects resembles the CGI Hulk in The Incredible Hulk, whom Norton is seen transforming into in the latter movie.)

A uniquely cinematic representational technique can be found in Arachnophobia, which I recently watched for the first time in years.  There’s a nicely executed scene in which Jeff Daniels’ character sees what he takes to be a tarantula-sized spider on the wall of his bedroom, and nervously approaches it only to find that it is merely the shadow of a clothes’ hanger affixed to the wall.  Now when you go back and watch the scene again and freeze the relevant frames, it seems pretty clear that it really was a spider (or perhaps a fake spider) rather than a clothes’ hanger that we, the audience, were originally looking at.  But of course, that doesn’t mean that Daniels’ character was wrong to conclude that it was just a hanger.  Though there does not seem to have been any trick photography in any of the relevant shots, the photography is nevertheless representing different things in the shots. The earlier shots are intended to represent the character’s perceptionof what was on the wall.  The later shots are intended to represent what really wason the wall.  Each shot crucially relies on resemblance, but in different ways -- resemblance to reality in the latter case, resemblance to someone’s perception of reality in the former.  

There’s a similar technique in David Mamet’s terrific movie The Spanish Prisoner.  Or maybe there isn’t -- the ambiguity is itself a further iteration of this uniquely cinematic method of representation via resemblance.  (Major plot spoilers follow!)  Campbell Scott’s character Joe Ross is the victim of an elaborate con game.  There’s a scene where the (ostensible) wealthy businessman Jimmy Dell, played by Steve Martin, gets Ross to sign what he takes to be a membership application in order to join (what is ostensibly) Dell’s private club.  (This is a completely straight role, by the way, and it may be my favorite Steve Martin performance.)  Ross finds out later, however, that what he had really signed was a document requesting political asylum in Venezuela -- an act which, given the details of the plot, is incriminating and gets him in trouble with the police.  The “application” (like the phony club and like Dell himself) was all part of the con.

Or was it?  If, via the magic of DVD, you go back and review the earlier signing scene, it is clear that the document Ross signed really was in fact labeled “Club Membership Decree,” and is not the similar-looking form requesting political asylum the police present him with later.  Now probably, as with Arachnophobia, the earlier scene is intended to represent, not what the character actually saw, but what he thoughthe saw -- though in this case most of the audience themselves won’t really notice the words “Club Membership Decree” (since they are largely obscured) until the second viewing.  So perhaps Ross really did see what he originally thought he saw, and the later document presented by the police is a forgery -- a con within a con?  Probably not -- but you’re not sure.

There are other elements like this in the movie.  For example, a crucial plot twist involves the subtle switching of a book Ross has in his custody, which contains the details of “The Process” he has developed for the company he works for, and which the con men are attempting to steal.  Yet if you watch the relevant scenes a second time, you find that there seems to be no point at which the switch could have been made.  Probably these scenes too are intended to represent, not what actually happened -- for the book really was switched -- but only Ross’s misperception of what happened, his failure to perceive the switch when it occurred.  And of course, Mamet knows that most people won’t go back obsessively to review the scenes and look for the switch: What matters to the story is what you thinkyou’re seeing earlier versus what you find out later.  

Again, though, you aren’t sure, precisely because there are enough twists in the con that you come to question everything you think you’ve seen, including every apparent revelation of earlier deception.  Hence, the ending of the movie appears to tie things up more or less tidily; I’ve seen the movie several times and I don’t see any clear way in which the denouement could be other than it seems.  Yet I’m not certain Mamet hasn’t somehow conned us, the audience, one last time with this apparent tidiness -- which is, perhaps, the point.  And a point that probably couldn’t be made as effectively in a medium other than film, with its unique ability to make use of resemblance as a means of representing or misrepresenting reality.  

(Nor is The Spanish Prisoner of merely epistemological interest.  The compelling aesthetic of this movie -- its look and especially its stylized dialogue, which is unusual even for a Mamet screenplay -- deserves a write-up of its own.)


John Paul the Great Academy

John Paul the Great Academy in Lafayette, Louisiana is a fine Catholic college preparatory institution promoting the classical curriculum, the Thomistic intellectual tradition, and fidelity to the teaching of the Church.  Unfortunately, the Academy is suddenly facing the prospect of closure and is urgently in need of the prayers and financial assistance of those sympathetic to its mission.  Take a look at the school’s website to find out more about the Academy, and please consider making a contribution.


Oerter contra the principle of causality

The Scholastic principle of causality states that any potential, if actualized, must be actualized by something already actual.  (It is also sometimes formulated as the thesis that whatever is moved is moved by another or whatever is changed is changed by another.  But the more technical way of stating it is less potentially misleading for readers unacquainted with Scholastic thinking, who are bound to read things into terms like “motion” or “change” that Scholastic writers do not intend.)

In an earlier post I responded to an objection to the principle raised by physicist Robert Oerter, who has, at his blog, been writing up a series of critical posts on my book The Last Superstition.  Oerter has now posted two further installments in his series, which develop and defend his criticism of the principle of causality.  Let’s take a look.

Quantum mechanics and causality

Recall that in an earlier post Oerter claimed that quantum mechanics casts doubt on the principle of causality insofar as it describes “systems that change from one state to another without any apparent physical ‘trigger.’”  Recall also that I pointed out that it is simply a fallacy to infer from the premise that QM describes such-and-such a state without describing its cause to the conclusion that QM shows that such-and-such a state has no cause.

In the first of the two further installments he’s posted since my response, Oerter replies to this sort of objection as follows:

This is a valid point.  Just because quantum mechanics…  is the most amazingly well-tested, most accurate, most far-reaching description of the universe that we have ever produced, we can't just conclude that it's the end of the story.  Maybe quantum mechanics is incomplete - maybe there is some further, more precise, theory that will tell us about the causes of electron transitions and radioactive decay…

This very point was raised in a famous paper by Einstein, Podolsky, and Rosen, who argued in 1935 that quantum mechanics must be incomplete…  An [sic] major advance came in 1964, when John Bell showed that (under a very general set of assumptions) any attempt to “complete” quantum mechanics would end up making predictions that differed from those of QM.  This led to a series of experiments designed to look for such differences.  The upshot: quantum mechanics has come out the winner in every test to date… 

[A]ny additional “causes” added to quantum mechanics will result in violations of quantum mechanical predictions.

Let's suppose that there is some physical property - something not included in the quantum mechanical description - that determines for each atom exactly when the electron will decay.  Call it property A.  Since property A is a physical property, it must have some physical effect.  If it has some physical effect, then it must be possible to separate out systems with one value of property A from systems with some other value.  That is, we can use property A as a filter…

Applying this filter, we separate out a subset from our original set of identically prepared atoms.  This subset, having a physical difference from the original set, will have a measurably different set of physical properties… Thus, this subset will violate the rules of quantum mechanics. 

Now, I put it to you that the 100-year history of successful predictions of quantum mechanics strongly suggests that there are no such additional physical properties…

End quote.  Now, to see what is wrong with this, recall the analogy I drew in my previous post with Kepler’s laws of planetary motion.  I noted that it would be fallacious to argue from the premise that Kepler’s laws describe the orbits of the planets without making reference to any cause of those orbits to the conclusion that Kepler’s laws show that the orbits of the planets have no cause.  And it would remain fallacious whatever you think about Kepler’s laws and whether or not you think the orbits of the planets have a cause.  For the point has nothing to do with the truth or falsity of either the premise or the conclusion.  It has to do instead with the logical relationship between the premise and conclusion.  The premise doesn’t entail the conclusion, and it doesn’t even make the conclusion more probable.  It is evidentially irrelevant to the conclusion.

Hence, suppose someone who insisted that Kepler’s laws do show that the planetary orbits have no cause responded to criticism of this fallacious inference by saying: “That’s a valid point.  Even though Kepler’s laws have had tremendous predictive success, they may not be the end of the story.  Maybe some future theory will posit some heretofore unknown massive bodies additional to the ones we already know about (the sun, planets, asteroids, etc.), which make the planets orbit the sun in just the way they do.  But the problem is that if there were such further bodies, they would influence the ones we do know about in such a way that their behavior would not match Kepler’s predictions.  So the success of Kepler’s laws strongly suggests that there are no such additional bodies.  So Kepler’s laws really do give us reason to doubt that the orbits of the planets have any cause.”

Such a response would, of course, completely miss the point.  For the point has nothing at all to do with the empirical question of whether there exist some heretofore unknown bodies additional to the sun, planets, asteroids, etc. which exert a causal influence on the rest of the solar system.  The point is much simpler (though also much deeper) than that sort of issue.  It is not a point about the existence of causes of this or that particular kind,but a point about causality as such.  And the point is that Kepler’s laws, which merely describe the behavior of the planets, tell you nothing one way or the other about why the planets behave that way.  They are not even addressing that question.  Hence they cannot answer that question.  Nor (we might note for those who eschew metaphysics) can they tell you whether the question is a good question, whether it has any answer in the first place, etc.  To the issue at hand, they are simply irrelevant.

Now the same thing is true of the relationship between QM and the principle of causality.  To point out that it is fallacious to infer from the premise that QM describes such-and-such a state without describing its cause to the conclusion that QM shows that such-and-such a state has no cause, is not to say that for all we know there may be some heretofore undiscovered physical property which exerts an influence on the energy level of the electron (or whatever).  The point is much simpler (though also much deeper) than that sort of issue.  It is that QM, which merely describesthe behavior of a system, tells you nothing one way or the other about whythe system behaves that way.  It also tells you nothing one way or the other about whether the question of why it behaves that way is a good question, whether it has any answer in the first place, etc.  To the issue at hand, QM is simply irrelevant.

This naturally brings us to another objection to his position that Oerter considers in his recent post, to the effect that the principle of causality is “a metaphysical premise that can't be contradicted by any possible set of observations.”  Oerter’s reply is that to insist, on metaphysical grounds, that the actualization of a potential must always have a cause is either to beg the question against him, or to rest one’s position on definitions of the key terms (“actuality,” “potentiality,” “change,” etc.) without giving any reason to think that the terms so defined really capture anything in the real world.

To see what is wrong with this response, consider once again the fallacious inference from the premise that Kepler’s laws describe the orbits of the planets without making reference to any cause of those orbits to the conclusion that Kepler’s laws show that the orbits of the planets have no cause.  Suppose that when you pointed out the fallaciousness of this inference to someone who made it, he replied: “Your position either begs the question against me or rests on arbitrary definitions!”  Obviously this too would simply miss the point, since the criticism of the inference in question was not: “The orbits of the planets do have a cause, here’s my theory about what that cause is, here are the technical terms my theory makes use of, etc.”  The criticism was rather: “Whether or not the orbits of the planets really do have a cause, the inference you are making is fallacious, because Kepler’s laws by themselves aren’t even relevant to that particular question.”  Similarly, the inference from the premise that QM describes such-and-such a state without describing its cause to the conclusion that QM shows that such-and-such a state has no cause is fallacious, and it remains fallacious whether or not the principle of causality is true, whether or not the definitions of its key terms have any application to reality, etc.  Even if the Aristotelian position turned out to be false, quantum mechanicswouldn’t be what falsifies it.

Oerter also addresses another potential objection to his position, to the effect that “the laws of quantum mechanics are the cause of the change [i.e. the change described in examples of the sort Oerter appeals to].”  The first part of Oerter’s response is as follows:

This objection can be dismissed easily.  The question is what causes the change to happen at the particular time it happens.  QM is silent on this question.

Further, in most philosophical views of physical laws, the laws have no causal efficacy.  For instance, we might think of laws as just descriptions of the way things actually behave.  But a description of how something happens is not a cause of it happening.  So, the moon's orbit around the earth isn't caused by the law of gravity.  It's caused by the actual gravity of the actual earth. 

Now as it happens I more or less agree with what Oerter says here.  Indeed, it is ironic that he should say it, because it actually supports my position rather than his.  Oerter writes that “we might think of laws as just descriptions of the way things actually behave.”  Exactly.  Laws -- including the laws enshrined in QM -- are descriptive.  They tell you what happens, but they do not tell you why it happens that way.  They may, of course, make reference to particular sorts of causal factors -- gravitation, mass, charge, etc. -- but the explication of these factors itself simply amounts to a further description of whatthese causes do, not why they do it.  Indeed, the causality as such of gravitation, mass, etc. is, strictly speaking, irrelevant to the laws.  That A and B will behave in such-and-such a way is all the law qua law commits you to; that A is the cause of B drops out as irrelevant.  That is why Newton’s law of universal gravitation was so useful even when we had no clear idea of what gravity was or how it worked.  And that is why positivists could hold that causality was a pre-scientific holdover which could be dispensed with.  They were wrongto hold this, but the point is that they could hold it with a straight face in the first place only because the status of causality as such -- its nature and even its existence -- is something about which the laws of physics themselves (including the laws of QM) are silent.  

But the status of causality as such is precisely what the principle of causality is about.  And that is why QM has nothing to tell us about the principle of causality.  They are simply not addressing the same question.  Given that you have already determined on independentgrounds whether or not the principle of causality is true, QM may raise questions about how it is to be understood in contexts like that of the hydrogen atom (to allude to Oerter’s example).  But there is nothing special about QM in that regard.  One billiard ball knocking into another, melting and freezing, electromagnetism, gravitational attraction, plant and animal growth, volitional behavior, divine creation, all involve very different sorts of efficient causality.  There are also distinctions to be drawn between essentially ordered and accidentally ordered causes, between causes that contain what is in their effects formally and those that contain what is in their effects only virtually, between total causes and partial causes, between the causality of substances and that of accidents, and so forth.  If you think that all efficient causality reduces to some crude, deterministic billiard-ball model, then QM might seem to be a challenge to the very notion of causality.  (“Look, there’s no little billiard ball deterministically pushing the electron into a higher energy level!  Causality itself crumbles!”)  But no Aristotelian or Scholastic would buy this simplistic conception of efficient causality in the first place.  (Naturalist critics of Aristotelian-Scholastic arguments rarely beg one question at a time.  They beg whole books full of questions.)

The principle of causality itself does not make any claim about how exactly efficient causes operate in all of these diverse cases.  It just tells us that whatever the details turn out to be, any potential will only be actualized by something already actual.  How does this work out in the case of QM?  This brings us to the second part of Oerter’s response to the claim that the laws of QM are the cause of change.  He writes:

Finally, even if we think of physical laws as having some sort of actual existence and causal efficacy, well, the laws of QM exist right at the moment the electron is excited, so by this view the electron should immediately decay.  In Aristotelian terms, we are looking for the efficient cause: the thing that brings about the change at the instant it occurs.  The laws of physics apply equally to all times; they can't be the reason something happens at some particular time.

(It seems to me that the laws of physics could be considered the formal cause in Aristotelian language.  But Feser says that modern philosophers have abandoned formal (as well as final) causes.  Does anyone know if laws can, or cannot, be considered formal causes?)

The answer to this latter question is: No, laws are not formal causes.  Nor do laws have any sort of independent existence or efficacy as efficient causes.  The correct thing to say from an Aristotelian point of view is rather something like this: Natural substances have essences or substantial forms that ground their characteristic patterns of operation.  For instance, it is in virtue of the substantial form of a tree that it tends to sink roots and grow branches; it is in virtue of the substantial form of water that it tends to freeze at one temperature and boil at another temperature; it is in virtue of something common to the substantial forms of material objects in general that they exert a gravitational pull on each other; and so forth.  Now a “law of nature” is a description of these patterns, a description of how things will tend to operate given their natures, essences, or substantial forms.  The existence and operation of laws of nature thus presupposes the existence and operation of concrete natural substances.  Indeed, strictly speaking it is not the laws that exist and operate; “laws” are mere abstractions from the concrete substances.  What exist and operate are the concrete substances themselves.  The laws are not even formal causes but rather mere descriptions of how things operate given their formal causes, i.e. their substantial forms.  (See chapter 6 of David Oderberg’s Real Essentialism for an important recent treatment of laws of nature from an Aristotelian-Thomistic point of view.) 

[This is, by the way, why “laws of nature” don’t really explain anything, at least not ultimately.  The very idea is a holdover from a time when Descartes, Newton, and Co. wanted to chuck out the Aristotelian framework, and replaced the idea that things operate according to intrinsic natures or substantial forms with the idea of operation according to externally imposed divine commands or “laws.”  Stripped of this theological context, the notion of a “law” must either be cashed out in Aristotelian terms of the kind suggested above, or in other metaphysical terms equally unwelcome to the naturalist, or -- as Nancy Cartwright has pointed out -- collapse into incoherence.  It is ironic that atheists so unreflectively help themselves to an inherently theological idea, albeit an idea derived from modernist rather than Scholastic theology.]

In the case of the hydrogen atom (once again to appeal to Oerter’s example), what we have is a concrete system that behaves in the way described by QM.  Now as I have noted before, whether to give QM a realist (as opposed to an instrumentalist) interpretation in the first place is itself a vexed metaphysical question.  And since it is a metaphysical question, it is precisely the sort of question to which we can legitimately bring to bear considerations like the principle of causality.  So even if there were some conflict between that principle and QM (which, as I have argued, there is not) it wouldn’t follow that we’d have to give up either.  If (as I would claim) we have independent reason to affirm the principle of causality, what would follow from such a conflict is that we should take an instrumentalist rather than realist view of QM -- a position some philosophers and scientists with no Aristotelian ax to grind would adopt in any case.

An interpretation of QM that is both Aristotelian and realist will, naturally, insist that it is not the laws of QM themselves that cause anything, since they are mere abstractions from concrete systems operating in accordance with their substantial forms.  Hence it is in virtue of the substantial form of a hydrogen atom that it will behave in the manner described by QM, just as it is by virtue of the substantial forms of material things in general that they will exert a gravitational attraction on one another.  Now for the Aristotelian, the substantial form of an inanimate substance is not the efficient cause of its natural operations; rather, those operations flow “spontaneously” from it, precisely because it is in the nature of the substance to operate in those ways.  (See James Weisheipl’s Nature and Motion in the Middle Ages for an important treatment of the subject.)  Hence that a planet exerts a gravitational pull is just something it does by virtue of its nature or substantial form; it does not need a continuously operating efficient cause to make it exert such a pull.  That does not mean that there is in no sense an efficient cause of a thing’s natural operations, but that efficient cause is just that which gave the substance in question its substantial form in the first place, i.e. that which generated the substance or brought it into being.  It is not something that needs continuously to operate after the thing is brought into being.  Hence the efficient cause of a planet’s exerting a gravitational pull on other objects is just whatever natural processes brought that planet into existence millions of years ago, thereby giving it the nature or substantial form it has.  Its exerting that pull is now something it just does “spontaneously,” by virtue of its nature.  (Mind you, that does not mean that it can exist or operate even for a moment without a divine sustaining cause; it cannot do so, for reasons I spell out in my ACPQarticle “Existential Inertia and the Five Ways.”  But that is a separate issue.  What I am talking about here is whether there needs to be some efficient cause alongside it within the natural order that causes it to exert a gravitational pull.)

Now, along the same lines, we might say that the hydrogen atom also behaves as it does “spontaneously,” simply by virtue of having the substantial form it does.  Why do the electron transitions occur in just the pattern they do?  Because that’s the sort of thing that happens in anything having the substantial form of a hydrogen atom, just as gravitational attraction is the sort of thing that naturally happens in anything having a substantial form of the sort typical of material objects.  What is the efficient cause of this pattern?  The efficient cause is whatever brought a particular hydrogen atom into existence, just as the efficient cause of gravitational attraction is whatever brought a particular material object into existence.  That is one way, anyway, of giving an Aristotelian interpretation of QM phenomena of the sort cited by Oerter, and it is intended only as a sketch made for purposes of illustration rather than a completely worked out account.  But it shows how QM can be naturally fitted into the Aristotelian framework using concepts that already exist within the latter.

Of course, critics of Aristotelianism will reject this way of interpreting what is going on.  Fine and dandy.  (Though pleasedon’t waste everyone’s time with sophomoric Molière-style “dormitive virtue” objections to substantial forms.  I have explained why this objection is no good in The Last Superstition and Aquinas.)  The point is that QM itself gives one no reason whatsoever to reject it.  If the critics of the Aristotelian position are to find rational grounds for rejecting it, they must look elsewhere.

Newton and local motion

In the second of the two installments he’s posted since my initial response to him, Oerter raises the hoary objection from Newton’s law of inertia against the principle that whatever is moved is moved by another.  Now, as I have already noted, the less misleading way of stating the principle is as the thesis that any potential, if actualized, must be actualized by something already actual.  And when it is put that way, it is less obvious that there is any conflict with Newton’s law.  After all, Newton’s law tells us that every body continues in its state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.  And how, exactly, does this contradict the thesis that any potential, if actualized, must be actualized by something already actual?
The answer is that there is no conflict at all, because (once again) the principle of causality and the laws of physics are not even addressing the same question.  Now I discussed this issue briefly in The Last Superstition, and it is to what I said there that Oerter is responding.  But I addressed the issue at greater length in Aquinas(at pp. 76-79), which it seems Oerter has not read.  And I address it at much greater length still in my paper “The medieval principle of motion and the modern principle of inertia,” which is forthcoming in the Proceedings of the Society for Medieval Logic and Metaphysics (and which, when it appears, should be available online as well as in print).  

I’m not going to repeat everything I’ve said in Aquinasor preempt what I say in the forthcoming paper, but some general remarks should suffice for present purposes.  There are five general reasons why the purported conflict between Newton’s law and the principle of causality is illusory (reasons I develop at length in the paper).  First, there would be no formal contradiction between the two even if they were using “motion” in the same sense.  For like Kepler’s laws and the laws of QM, Newton’s law is descriptive.  It tells us how a body behaves, but not whyit behaves that way.  Thus the law does not rule out the thesis that the reason a body so behaves is because of a “mover” which actualizes its potencies for motion.  (To be sure, the law does rule out any scenario where a body continues at rest or uniform rectilinear motion while acted upon by physical forces impressed upon it.  But -- to appeal once again to the analogy with Kepler’s laws -- the principle of causality no more requires that what actualizes a potency is, specifically, a physical force of this sort than to affirm a cause of the orbits of the planets requires positing a special kind of massive body additional to the sun, planets, asteroids, etc.)

Second, Newton’s law and the principle of causality are not in fact using “motion” in precisely the same sense in the first place.  Newton’s law pertains to local motion specifically, i.e. change with respect to place.  The principle of causality applies to change of any kind, which includes not only local motion but change with respect to quantity, change with respect to quality, and change from one substance to another.  Now some might object that these other sorts of change can all be reduced to local motion.  I think that is quite false, but that is neither here nor there for present purposes.  For the deeper point is that when the principle of causality speaks of motion (local or otherwise) what it is talking about is the actualization of potentials.  And Newton’s law simply has nothing whatsoever to say about that.  In particular, when Newton’s law says that a body in motion will tend to stay in motion, it is not asserting that a potential which is being actualized will continue being actualized.  Even if it were suggested that Newton’s law entails this, the point is that that isn’t what the principle of inertia itself, as understood within physics, is saying.  Indeed, the whole aim of early modern physics of the sort practiced by Newton was to provide a description of nature that sidestepped the whole Aristotelian-Scholastic apparatus of actuality and potentiality, substantial forms, and the like.  Modern physics didn’t offer different answers to the questions the Scholastics were asking.  It simply changed the subject.

A third point is that Newtonian inertial motion is often characterized as a “state” -- that is, as the absence of any real change.  Now if such motion really is a state, then there is no conflict with the principle of causality, for if inertial motion involves no real change, than it involves no actualization of potential -- in which case, obviously, it involves no actualization of a potential without a cause.  Indeed, since Newton’s law says that a genuine change in an object’s local motion can occur only if a force acts upon it, the law implicitly affirmsthe principle of causality!  Hence if inertial motion really is a “state,” then what Newton and his Aristotelian predecessors disagreed about was notwhether genuine change requires a cause, but only about whether local motion of a uniform rectilinear sort counts as genuine change.  

A fourth point is that those who assert a conflict between Newton and Aristotle often direct their attacks at a straw man.  In particular, it is sometimes thought that Aristotle and Aquinas maintained that no object can persist in any local motion unless some mover is continuously conjoined to it as an efficient cause.  But in fact they denied this; their view was that an object will tend to move toward its “natural place” simply by virtue of its substantial form, and will do so even in the absence of that which imparted this form, and thus in the absence of that which is the efficient cause of their local motion.  (This is related to the point made earlier about the operations that a substance will carry out “spontaneously” given its substantial form.  And here too, Weisheipl’s book is the place to look for a detailed treatment of the subject.)  To be sure, the idea of “natural place” is a piece of Aristotelian physics (as opposed to metaphysics) that is obsolete; and the violent (as opposed to natural) motions of objects were thought to require some conjoined mover.  But all of that is beside the point.  For the pointis that Aristotle’s and Aquinas’s principle of causality in fact did not presuppose that local motion as such requires a continuously conjoined physical cause.

Finally, and as all of this indicates, there can be no conflict between Newton’s law and the principle of causality because the former is a thesis of natural science and the latter a thesis of metaphysics -- or more precisely, of that branch of metaphysics known as the philosophy of nature.  As Bertrand Russell and others with no Aristotelian or theological ax to grind have emphasized, what physics gives us is really only the abstract mathematical structure of the material world.  It does not tell us what fills out that structure, does not tell us the intrinsic nature of the material world.  But that iswhat metaphysics, and in particular the philosophy of nature, are concerned with.  Moreover, the philosophy of nature, as modern Scholastics have understood it, tells us what the natural world must be like whatever the specific laws of physics, chemistry, etc. turn out to be.  And the Scholastic position is that the distinction between actuality and potentiality, the principle of causality, and other fundamental elements of the Aristotelian conception of nature are among the preconditions of any possible material world susceptible of scientific study.

That is why no findings of empirical science can undermine the claims of metaphysics and the philosophy of nature.  It is also why no findings of empirical science can undermine the Aristotelian-Thomistic arguments for the existence of God, for these are grounded in premises drawn, not from natural science, but from metaphysics and the philosophy of nature.  Now that does not mean that these arguments of natural theology are not susceptible of rational evaluation and criticism.  What it means is that such evaluation and criticism will have to be philosophical and metaphysical, rather than empirical, in nature.  Nor is natural theology in this regard at all different from atheism.  Atheists who think they are arguing from “purely scientific” premises never really are.  They are, without exception, arguing from metaphysical assumptions -- and usually unexamined ones at that -- that are first read into empirical science and then read back out, like the rabbit the magician can pull out of the hat only because he’s first hidden it there.

Readers who disagree with these claims are cordially invited to refute them -- without either begging the question or smuggling in metaphysical assumptions of precisely the sort they deny making.  Good luck with that.


Aquinas on audio

Your print copy of Aquinasis dog-eared.  You’ve worn out your Kindle reading the e-book version.  If only you could give your eyes a rest!  And avoid the car accidents you’re risking by flipping though the book on the way to work!  Well, you’re in luck: Aquinas is now available in an audio version
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