Monday, May 14, 2012
Oerter on universals and causality
George Mason University physicist (and author of The Theory of Almost Everything) Robert Oerter is writing up a series of posts on my book The Last Superstition over at his blog. Oerter is critical but he engages the book seriously and in good faith. He’s presented a couple of objections so far, and they merit a response. So, here’s a response.
Universals and secondary qualities
In the book, I defend a realist (as opposed to nominalist or conceptualist) approach to the problem of universals. Realism comes in several varieties, but they all agree that at least some universals exist. A realist about circularity, for example, would hold that there really is such a thing as circularity over and above individual circles, which the individual circles all instantiate; a realist about redness would hold that there really is such a thing as redness over and above individual red things, which the individual red things all instantiate; and so forth. (In the book I introduce the issue by way of Plato and Aristotle, but as should be clear to those who’ve read the whole book, the position I ultimately take is not the “extreme realism” of Plato nor even, exactly, the “moderate realism” of Aristotle. Rather, I endorse the “Scholastic realism” of Aquinas and other Scholastics, which is essentially a modified Aristotelian moderate realism on which universals exist either in the things which instantiate them or in intellects, but where the latter includes the divine intellect, in which they pre-exist as the archetypes according to which God creates. But that is neither here nor there with respect to Oerter’s objections.)
Oerter suggests that “redness” poses a problem for realism about universals. But it seems to me that he commits several fallacies. The first is that even if he succeeded in showing that “redness” was not a true universal, that wouldn’t entail that there are no universals at all. Indeed, even if it turned out that there were no true color universals, that would hardly show that there are no universals at all. Oerter’s criticisms appeal in part to scientific considerations, and yet many realists emphasize that scientific laws themselves necessarily appeal to universals. For example, force, mass, acceleration, energy, the speed of light, etc. are all universals -- the laws that make reference to these properties are not referring merely to this or that particular instance of mass, acceleration, or whatever, but to mass, acceleration, etc. wherever they are instantiated. Hence to appeal to science in order to refute realism about universals only kicks the problem up a level. Even if you get rid of universals in one domain, you just reintroduce them somewhere else.
Second, it isn’t clear that Oerter properly understands what is meant by calling something a “universal.” He puts great emphasis on the fact that not all cultures have the same color words we do, do not all distinguish red from other colors, etc. That makes it sound as if realists about universals are making some anthropological claim, to the effect that redness is a universal in the sense that a word for it can be found in all languages. But of course, that is not what the realist is claiming at all. When the realist says that mass or acceleration is a universal, he doesn’t mean that all cultures have words for these properties. He means that all instances of mass and acceleration (including those instances that existed before human beings came on the scene, those instances that exist in cultures which have no words for them, those instances that will exist if the day ever comes when there are no more human beings, etc.) are all instances of one and the same thing -- that there is something over and above these instances which they all instantiate or exemplify, and which could in some sense remain even if none of the instances existed. Similarly, when a realist claims that redness is a universal, he is not saying that all languages have a word for redness, that they all distinguish between colors in just the same ways, etc. He is making a claim about redness itself and the things that instantiate it, not a claim about our words for redness and its instances.
Alternatively, it may be that Oerter understands what the debate over universals is about but is simply committing a use/mention fallacy. He writes:
When someone says "The apple is red (nyian)" in Tiv, they are saying something very different than I am when I say that sentence. So it is clear that color is a culturally dependent quantity.
This is a bit like saying that since people used to think that “the morning star” and “the evening star” named different objects, it follows that the planet Venus is “culturally dependent” (whatever that could mean). The way we use terms for heavenly bodies is one thing; what is actually true of the heavenly bodies themselves is another. Similarly, the way we use terms for colors is one thing, and what is true of the colors themselves is another. In both cases, it is a fallacy to suppose that what is true of our usage of terms necessarily tells us anything about the nature of the things the terms are used to refer to.
Oerter also argues that the evidence for the mind-dependence of colors is reason to reject the claim that “redness” names a genuine universal. But here he is confusing the problem of universals with the question of whether colors are primary or secondary qualities. These are entirely distinct issues. Suppose, for the sake of argument, that we follow the tradition inaugurated by Galileo, Locke, and other early modern scientists and philosophers in distinguishing “redness” as common sense understands it (the way red looks to normal observers when they perceive it in ordinary circumstances) and redness as a property describable in terms of physics (in terms of surface reflectance properties etc.). Then we can distinguish between RED (in caps) and red (in italics) as follows:
RED: the qualitative character of the color sensations had by a normal observer when he looks at fire engines, “Stop” signs, Superman’s cape, etc. (which is different from the qualitative character of the sensations had by e.g. a color blind observer when looking at these objects, and different from the qualitative character of the sensations had by a normal observer when looking at the sky, at Batman’s cape, etc.)
red: whatever set of physical properties it is in fire engines, “Stop” signs, Superman’s cape, etc. that causes normal observers to have RED sensations (and which is different from those physical properties of the sky, Batman’s cape, etc. which cause normal observers to have sensations other than RED ones when looking at those things)
Now, even if we make this distinction, both RED and red are still themselves candidates for being universals. There is the instance of red present in this “Stop” sign, the instance of red present in that other “Stop” sign, the instance of red present in such-and-such a fire engine, and so forth. (Even if it turns out that there is no single set of physical properties present in every single red thing, that doesn’t make any difference either. For then we will still have a set of distinct kinds of red each of which is itself a kind of universal -- just as German shepherd is no less a universal than dog is.)
There is also the instance of RED represented by the sensation you are having now, the instance of RED represented by the sensation you had yesterday, the instance of RED represented by the sensation the guy sitting next to you is having, etc. (And even if it turns out that what you call RED and what I call RED are qualitatively different, that wouldn’t make any difference either. For then it will still be the case that every instance of RED in my sense of “RED” is an instance of the same one universal, and every instance of RED in your, different sense of “RED” is an instance of a different universal, and so forth. This no more shows that “RED” doesn’t name a universal than the fact that “bat” can mean either a certain kind of animal or a certain piece of sports equipment shows that “bat” doesn’t name a universal.)
The principle of causality
Oerter also takes issue with my claim that any potential must be actualized by something already actual (which is one formulation of the Scholastic “principle of causality”). Oerter says that my argument for this claim assumes that “a potentiality can't be actualized by nothing (because then there would be no way to explain when the change occurs).” He goes on to object:
This step only works if you assume that there is always a way to explain when a change occurs. But what if there isn't?
This might seem a strange complaint - unless you know something about quantum mechanics.
And in a follow-up post he presents an example from QM he evidently takes to be a counterexample to the principle of causality:
[O]ver the last hundred years, physicists have discovered systems that change from one state to another without any apparent physical “trigger.” These systems are described by quantum mechanics.
The simplest such system is the hydrogen atom. It's just an electron bound to a proton. Two particles - that's about as simple as you can get. According to QM, the electron can occupy one of a discrete set of energy levels. The electron can be excited to a higher energy level by absorbing a photon…
When the electron drops from a higher energy level to a lower level, it emits a photon: a quantum of light…
Quantum mechanics describes this process beautifully, but it only predicts the average time the electron will stay in the higher energy level. It doesn't give any clue as to the specific time the electron will drop to the lower level. More precisely, the transition rate (the probability of a transition per unit time) is constant: it doesn't matter how long it has been since the atom was excited, the transition rate stays the same…
When you first encounter this, you can't quite wrap your brain around it. Surely there must be some internal mechanism, some kind of clock, that ticks along and finally "goes off," causing the transition!
But no such mechanism has ever been found. QM has had an unexcelled record of accurate predictions, without any need for such a mechanism…
Now so far none of this is even a prima facie counterexample to the principle of causality. From:
1. QM describes the transition of the electron without making reference to a cause.
it simply does not follow that:
2. QM shows that the transition of the electron has no cause.
Such an inference would be no better than:
3. Kepler’s laws describe the orbits of the planets without making reference to any cause of those orbits, so
4. Kepler’s laws show that the orbits of the planets have no cause.
Even if for some reason you think that the orbits have no cause, Kepler’s laws give you no reason to doubt that they have one. And even if you think the transition of the electron has no cause, QM gives you no reason to doubt that it does.
Or doesn’t it? Oerter goes on to add:
Further, we have good reason to suspect that, if there were such a mechanism, then QM would not be accurate in its predictions. (I'll come back to this point in a later post.) So, the absence of violations of QM is evidence that Feser's expectation - that there is always a reason for a change to happen when it does - is just wrong.
Well, obviously we’ll have to wait until this later post to see exactly what he thinks this reason is; until then Oerter hasn’t really given us any reason to doubt the principle of causality. But even before he gives it, it is hard to see what such a reason might be. What does Oerter have in mind by a “mechanism,” the presence of which is incompatible with the accuracy of QM? Does he mean something acting deterministically? The principle of causality doesn’t require that. It requires only that a potency be actualized by something already actual; whether that something, whatever it is, actualizes potencies according some sort of pattern --deterministic or otherwise -- is another matter altogether. (The Scholastic holds, after all, that God caused the world, but does not hold that divine causality is deterministic, or probabilistic, or in some other relevant way comparable to the sort of causality one finds in physical systems.)
Indeed, showing that there cannot be any strict incompatibility between the accuracy of QM and the principle of causality is a pretty trivial task. Laplace and Maxwell had their demons, so to this grand tradition of thought experiments in physics, I’ll add my own. Consider Feser’s demon, who knows QM and causes electrons to transition between levels in a pattern consistent with what he’s read in his physics textbooks. Here we have a cause which (a) actualizes the potential of the electron to be at this level or that and (b) does so in a way consistent with the predictive accuracy of QM.
(For the dumber-than-usual New Atheist reader out there about to rush over to the Richard Dawkins Foundation combox to fill in the gang on Feser’s latest outrage, I suppose I ought to emphasize that I am not saying that any such demon exists, any more than Laplace or Maxwell were. Nor am I saying that the electron transition has a supernatural or preternatural cause of any sort. Indeed, I am saying nothing at all about what the cause of the electron transition might be. I am merely making the narrow point that there is no conflict between the accuracy of QM and the claim that the transition has some cause or other.)
Oerter ends his latest post with the remark that “It seems that physics is not, after all, irrelevant to metaphysics.” Well, I don’t think I ever said that it is irrelevant. But I would say that you are not going to read off any metaphysical results from physics without first reading some metaphysics into the physics. There is a reason why there has long been a debate over how to interpret QM, and indeed about whether QM ought to be given any sort of realist (as opposed to instrumentalist) interpretation in the first place. The reason is that it just isn’t at all clear from QM itself how to understand its underlying metaphysics. Hence, whenever buying a philosophical argumentum ad QM -- especially from a non-philosopher, even a smart and intellectually honest non-philosopher like Oerter -- make sure you get a receipt. Such arguments absolutely never perform as advertised.
P. Z. Feser?
Oerter makes some very kind remarks about me in his first post, which I appreciate. But he also compares me to P. Z. Myers -- which is, well, not so kind. I don’t think Oerter means any harm by the comparison; and obviously, like Myers I am not exactly a shrinking violet and am known to have my polemical moments. Still, the comparison isn’t fair. While I think polemics are occasionally justified, I have also made it clear that I do not think they always are. And for the most part I am polemical only with those who have themselves already been polemical. Nor is most of my work anywhere near as polemical as The Last Superstition. Myers, by contrast, never seems to trade in anything but snark and abuse. (I have addressed the question of when polemics are justifiable in a couple of earlier posts, here and here.)
Perhaps more importantly, Myers’s main claim to fame is the “Courtier’s reply” dodge, a blatantly question-begging attempt to rationalize his refusal to learn what his opponents have actually said before ridiculing and dismissing it. He never responds to serious, worthy critics.
By contrast, I just did. And I have responded (for the most part politely!) to other serious atheist and agnostic writers at length -- to the traditional objections to theistic arguments (from Hume, Kant, and others) in The Last Superstition and elsewhere, to J. L. Mackie and Anthony Kenny in Aquinas, to Bede Rundle and John Beaudoin in my American Catholic Philosophical Quarterly article “Existential Inertia and the Five Ways” (which you can read online by Googling the article title, scrolling down to about the fourth result, and clicking “Quick view”), to Paul Edwards here, and so on.
If Myers has ever presented a substantive reply to any serious theist, I’d love to hear about it. But I’m afraid this is more his speed.
Anyway, I thank Prof. Oerter for his kind words and worthwhile criticisms.