Holy Cyclops

In a comment to my post What’s Wrong with Modal Ontological Arguments, Kenny mentioned the Moorean Shift.  I want to take a few moments to look at it.

The Moorean Shift takes an argument whose form is modus ponens and converts it into one whose form is modus tollens, shifting premiss and conclusion in the process.  Thus, the argument

1.  p—>q
2.  p
Therefore,
3.  q

one of whose premisses is p and whose conclusion is q, becomes the argument

1.  ~q—>~p
2.  ~q
Therefore,
3.  ~p

one of whose premisses is ~q and whose conclusion is ~p.

The idea is that while accepting the premiss p—>q (which is rewritten in its equivalent contrapositive form ~q—>~p), the person making the Moorean Shift finds ~q more likely than he finds p, so instead of arguing from p’s truth to q’s truth, he argues from q’s falsity to p’s falsity. 

I see nothing wrong with this approach.  When evaluating an argument’s soundness, we must evaluate the truth-values of its premisses.  If one finds q more likely to be false than p is to be true, then he will be more inclined to view the second argument as sound than the first one; conversely, if one finds p more likely to be true than q is to be false, then he will be more inclined to view the first argument as sound than the second one.

For example, one might argue

1v.  If tigers are vegetarians, then tigers do not eat meat
2v.  Tigers are vegetarians
Therefore,
3v.  Tigers do not eat meat

But, while accepting premiss (1v), one might think that premiss (2v) is simply not true, and that the argument is therefore unsound; and if he also thinks that the conclusion (3v) is true, he might construct the new argument

1c.  If tigers eat meat, then tigers are not vegetarians
2c.  Tigers eat meat
3c.  Tigers are not vegetarians

Naturally, one finds the second argument sound but the first one unsound.

The difficulty with the Moorean Shift isn’t the Shift itself, which is entirely legitimate, but rather a linguistic problem in Moore’s use of it against philosophical skepticism that has nothing intrinsically to do with the Shift.  The philosophical skeptic thinks that one cannot know that he isn’t dreaming, or hallucinating, or a brain in a vat, or otherwise deluded about what appears to be true.  G.E. Moore argued against philosophical skepticism by holding up his hand and saying, “Here is a hand before me,” and claiming that since he knew his hand was before him, he knew something about empirical reality, and therefore philosophical skepticism was defeated.  He argued, in other words, in the following way (see Wikipedia entry Here Is a Hand):

Let S be an epistemic agent; let p be some skeptical possibility, like S’s dreaming or hallucinating or being a brain in a vat; let q be a knowledge claim about the world, like S’s hand being held before him.  Then the philosophical skeptic argues that

1s.  If S doesn’t know that ~p, then S doesn’t know that q  (If S doesn’t know that he isn’t dreaming, then S doesn’t know putative fact q about the world—in particular, S doesn’t know that his hand is held out before him)
2s.  S doesn’t know that ~p  (S doesn’t know that he isn’t dreaming)
Therefore,
3s.  S doesn’t know that q  (S doesn’t know putative fact q about the world—in particular, S doesn’t know that his hand is held out before him)

and Moore replies

1m.  If S knows that q, then S knows that ~p  (If S knows putative fact q about the world—in particular, that his hand is held out before him—then S knows that he isn’t dreaming)
2m.  S knows that q  (S knows putative fact q about the world—in particular, that his hand is held out before him)
Therefore,
3m.  S knows that ~p  (S knows he isn’t dreaming)

Moore holds out his hand in front of him and says, “Here is a hand.”  Since, he thinks, he knows that there is a hand before him (”S knows that q”), he also knows that philosophical skepticism is false (”S knows that ~p”). 

Put this way, it seems that a simple linguistic or conceptual mistake is being made.  The philosophical skeptic says that if one cannot know that he is not, say, a brain in a vat (or some other skeptical possibility, like being a dreamer or a self-generator of the appearances), then he cannot know any empirical fact; and then claims that one cannot know that he is not, say, a brain in a vat; and therefore one cannot know any empirical fact.  Moore says that one can know an empirical fact, and therefore can know that the skeptical possibility is false; but the philosophical skeptic’s use of the word know and Moore’s use of the word know seem to differ.  The philosophical skeptic’s use of the word seems intended to imply complete and utter certainty, beyond Cartesian doubt.  Moore’s use of the word seems only intended to imply everyday certainty, beyond everyday doubt.  (We don’t, after all, walk around muttering to ourselves, “Is this really my hand before me?”) 

It would be hard to believe that an acknowledged great philosopher like Moore would have missed this, so perhaps we can read his Moorean Shift, as applied to the philosophical skeptic’s argument, differently.  Perhaps all he means is that he finds it more likely that the everyday assertion that there is a hand before him is true than that the pathological assertion that, say, he is a brain in a vat, is true, and that he therefore accepts (1m)-(3m) rather than (1s)-(3s).  Unfortunately, that just seems like another way of saying that his use of the word know doesn’t imply complete and utter certainty, beyond Cartesian doubt, but only implies everyday certainty rather than philosophical certainty.  Lots of philosophical skeptics, I’m sure, would also accept (1m)-(3m), on that same everyday use of the word know—philosophical skeptics don’t go around muttering to themselves, “Gee, I wonder if this is a hand before me,” in everyday life, either.  The philosophical skeptic’s argument is directed at the conceivability of Cartesian doubt—at the conceivability of our being brains in vats, for example—but I imagine that most philosophical skeptics would nevertheless endorse Moore’s argument for the everyday sense of know.  So, it still seems that Moore and the philosophical skeptic are simply not addressing the same point.  Moore seems not to be addressing Cartesian doubt at all. 

But the Moorean Shift remains a perfectly reasonable way of choosing among deductively valid arguments, since what one wants to accept are sound arguments, which involves assigning truth-values, or at least likely truth-values, to a valid argument’s premisses.  And that’s all the Moorean Shift does:  It says, “I find this premiss more likely than that one, and therefore find this argument more likely to be sound than that one.”

I was reading Alvin Plantinga’s The Nature of Necessity yesterday, and he quoted and analyzed, in great detail, a couple of passages, one from William Kneale and one from W.V.O. Quine, whose quotation and analysis reminded me once again that professional philosophers sometimes make silly mistakes.

The discussion was about essential and accidental (necessary and contingent) properties.  Kneale’s anti-essentialist argument was, in my reconstruction from memory, that one couldn’t say that the number twelve was essentially composite, because surely it is only a contingent fact that the number of apostles was twelve, so the number of apostles couldn’t be essentially composite; but since the number of apostles and the number twelve are the same number, twelve can’t be essentially composite.

I’ve rendered it in more detail than he did in the quoted passage.  But one can easily see the mistake:  An equivocation on the meaning of “The number of apostles.”  Does “the number of apostles” mean “the actual number of apostles (i.e., twelve),” or does “the number of apostles” mean “the possible number of apostles (i.e., twelve or eleven or thirteen or…)”?  “The number of apostles” and “twelve” denote the same number only if “the number of apostles” is intended as “the actual number of apostles (i.e., twelve)”; if one intends “the number of apostles” as “the possible number of apostles (i.e., twelve or eleven or thirteen or…),” then one can no longer equate twelve with the number of apostles.  One may either say

1. Twelve is a composite number.
2. The (actual) number of apostles is twelve.
3. Therefore, the (actual) number of apostles is composite.

or

1. Twelve is a composite number.
2. The (possible) number of apostles might be twelve but might be some other number, like eleven or thirteen.
3. Therefore, the (possible) number of apostles might be composite but might not be.

In the first case, “the (actual) number of apostles” is a Kripkean “rigid designator,” if I’m remembering his terminology correctly, always equalling twelve and therefore always composite, just like twelve—rendering the argument against essentialism toothless.  In the second case, “the (possible) number of apostles” is a non-rigid designator, not always composite but also not always equalling twelve—again rendering the argument against essentialism toothless.  Only if one could argue that the number twelve had the kind of fluidity of designation that “the (possible) number of apostles” has could one go on to argue that twelve is not necessarily composite—but, of course, that can’t be done.

Quine’s argument, again in my reconstruction of it, was that whether or not a property is thought to be necessary depends on how we describe the property-bearer—that properties of objects are not essentially necessary or non-necessary but are, rather, only necessary or non-necessary relative to our descriptions of those objects.  His example is as follows:  We might normally say that, in some sense, mathematicians are necessarily rational but are not necessarily bipedal, and that cyclists are not necessarily rational but are necessarily bipedal.  (Let’s set aside any question about either the rationality of all mathematicians or the bipedality of all cyclists.)  But suppose a mathematician is also a cyclist.  Then are we to say that he is both necessarily rational and not necessarily bipedal and also not necessarily rational but necessarily bipedal—a contradiction (a pair of them, really)?  Our assessment changes with our change in description:  We say that the mathematician-cyclist is both necessarily rational and necessarily bipedal.

I’m sure I’m not rendering his argument as persuasively as he did, but its main point is the contradiction given.  Two points can be made about this:  First, it may be that saying that mathematicians are not necessarily bipedal, and that cyclists are not necessarily rational, is saying something too strong.  We do not know of all mathematicians that they are not necessarily bipedal; perhaps some of them (like the mathematician-cyclist) are necessarily bipedal, while others aren’t.  (Similarly for cyclists and the non-necessity of their being rational.)  What we can justifiably say is that mathematicians are necessarily rational and possibly bipedal (and similarly that cyclists are possibly rational and necessarily bipedal).  But then the contradiction vanishes:  The mathematician-cyclist is necessarily rational and possibly bipedal, and he is possibly rational and necessarily bipedal, and that doesn’t contradict his being necessarily rational and necessarily bipedal.  Second—and, in my view, the more important point, and the one that qualifies Quine’s argument for inclusion in a post entitled “Silly Philosophical Mistakes”—is that while it is true that we make our descriptions on the basis of what we know, or on the basis of our present interests or purposes, rather than on the basis of what is true, and that for that reason our ascriptions of modal status with respect to different properties will seem to vary according to our present interests and purposes—in contradiction to the essentialist view that necessary properties, at least, are essential to entities—it is nevertheless also true, in opposition to Quine, that while what we know of an object may change (so that we realize, when we learn that a mathematician is a cyclist, that he is not only necessarily rational, as we had thought, but that he is also necessarily bipedal), and that while our choice of description may vary according to our interests or purposes (so that we may know very well that a mathematician is also a cyclist but may or may not choose to ignore it for the moment, resulting in our sometimes describing the mathematician-cyclist as necessarily rational and possibly bipedal and in our sometimes describing the mathematician-cyclist as both necessarily rational and necessarily bipedal), neither our knowledge change nor our choice of description implies that what is true of the object changes or is somehow malleable.  At best, Quine’s is an argument for description-relativism; it isn’t, as he appears to want it to be, an argument for fact-relativism (or for relativism of modal facts to description).  (Even if Quine thinks that we know the facts about objects, that simply means that a description of the object that expresses those facts must be complete in order to capture all of those facts—an incomplete description, chosen for our own reasons, might fail to capture all of those facts.)   

A few months ago, I attended a meeting at which the group leader used the word “perfect” in the following way:  Accept yourself as you are, for you are perfect; do not worry about the past, for the past is perfect. 

 I cringed.

Tonight, on the Science Fiction Channel’s program Battlestar Galactica, one of the characters, Gaius Baltar, gave what was supposed to be an inspirational speech to a group of followers in which he reasoned as follows:  God would not love you if you were imperfect; but God does love you.  This is God’s truth:  You are all perfect!

Again, I cringed.

When did “perfect” begin to be misused and abused this way?  The speaker at my meeting meant something like, “Accept yourself as you are; love yourself as you are.  Do not kick yourself or get down on yourself or overcriticize yourself for your flaws; human beings are imperfect, and you’re an imperfect human being, and that’s OK.  Accept the past as it is; it is unchangeable, and worrying about it won’t help anyone at all, least of all yourself.  Just accept it, and move on to doing what’s best and most constructive in the future.”  (I might have embellished her meaning a bit, but the gist of it is not to worry about either your flaws or the past, but just to love yourself and be loving now and in the future.)  “You are perfect” is not the same as “You should accept yourself as you are.”  Nor is “You should accept yourself as you are” synonymous with “You shouldn’t do anything to try to improve yourself.”  “Perfect” means “beyond any conceivable improvement.”  There are conceivable ways in which anyone could be a better person—if only by knowing one more language than he already knows, or by learning how to use the word “perfect”—and there are conceivable ways in which the past could be better than it was.  “You are perfect” does not mean “You are worthy of love,” as Gaius Baltar seems to have used it to mean. 

Why must people misuse and abuse a good English word?  Such misuse and abuse just makes it harder for people to communicate clearly with each other. 

The truly annoying thing is that it’s usually nice people using the word for noble purposes, trying to help people feel good about themselves and to stop being overly critical of themselves, who do this.  One wants to say, “I agree with your sentiment, but you need to express it differently.”  But, as I discovered at that meeting, not everyone understands what he’s doing wrong, even when it’s pointed out by more than one person, as was done then; the two of us were just categorized as “logical people”—as though being logical were optional!  As though logic were a hobby some people pursued but that other people were free to simply ignore.

This Humpty Dumpty language use, in which words mean whatever one wants them to mean, only ends up leading to confusion and to the acceptance of unjustified doctrines.  You get fuzzy thinking.  You get relativism and subjectivism and postmodernism.  (In a related vein, I’m reminded of a joke I just read:  What do you get when you cross a Mafioso and a postmodernist?  You get someone who makes you an offer you can’t understand.)  And, ultimately, you change the meaning of the word, and then a new word needs to be coined to express the old concept.  I can only shake my head and wonder why this happens.