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.
Can an Aristotelian metaphysician allow the possibility that the hydrogen atom simply has a propensity to behave in this way with a certain probability in a certain time interval, and that this propensity can manifest without the help of any outside agent? And if not, why not? What is metaphysically incoherent about that conception?
ReplyDeleteThanks, Rupert. The short answer is no. In this instance, if the motion of the electron is due to a "propensity" in the atom, then the electron's motion cannot be said to be uncaused. The electron's motion could not then be independent of the atom because, as you've stated, it's motion is due to something in the atom which causes the movement. As noted above, potency cannot raise itself to act because it does not currently exist, and what does not exist cannot be the agent of its act on pain of contradiction. If there is nothing in the atom which causes the movement, then the only alternative is something other than the atom.
ReplyDeleteThat said, the atom still needs the "help of [an] outside agent" because its existence is being actualized. Since self-actualization is impossible, the atom's ground is beyond itself.
You don't understand the notion of a propensity?
ReplyDeleteWhy should I believe all this?
ReplyDeleteI've been reading The Last Superstition and am on the arguments for realism. I can't help thinking these are word games. If you are right, then isn't it the case that every single thing that can be expressed by a noun must exist in some ideal "Form?" So there is a perfect Form "iPhone," and a perfect Form "Butternut Squash," and on and on. And tomorrow someone will invent a ScoogieWazzit, and suddenly as perfect Form ScoogieWazzit will exist. Huh?
ReplyDeleteThis is an old thread but a timeless topic, so:
ReplyDeleteRe: "...where the latter includes the divine intellect, in which they pre-exist as the archetypes according to which God creates."
But isn't this precisely the Platonic position? The real universals (supraformal and transcendent) are the Archetypes in the Divine Intellect. Also, Augustine's "seminal ideas". It is ultimately the uncreated Logos which is in question.
This is probably just a sad example of a person trying to beat a dead horse, but here are my little two cents.
ReplyDeleteI think an important distinction to make is that between genuine and non-genuine similarities. The first are entailed by a universal while the latter are not. For example, a genuine similarity is that between a dog and a cat. Both a dog and a cat actually share the similarity of having fur, and of sensing their surroundings. Thus, they both participate in an actual universal of being 'furry' and having 'sensation'. But, one might believe that a cat is like a dog in that a dog is cute like a dog. This is a matter of personal impressions, since it is not necessarily of a dog's or a cat's actual nature to be 'cute'. Now, the impression that we call 'cute' is actually itself a universal, as it can be discussed intelligibly and viewed as a concept.
To anyone looking for a scholastic realist view of QM, I recommend the book The Quantum Enigma by Wolfgang Smith
ReplyDelete