Monday, October 21, 2013

A Head Scratcher

Ed Feser has responded again, and it's a puzzler.

I will ignore the first part of his post, in which he is once again arguing against some argument that is not the argument I made.

Next, Feser points out that my objection, even if it worked against Ross, was irrelevant against Feser's own version of the argument.
For another thing, it is not just Ross’s views that are in question here, but mine.  And I can assure Oerter that what I am claiming is (2) rather than (1).  So, even if what he had to say in his latest post was relevant to the cogency of Ross’s version of the argument in question, it wouldn’t affect my own version of it.

Well, I never said I was arguing against Feser's version of the argument, I explicitly stated I was critiquing Ross's argument. And that is what I will continue to do here, though I may return to Feser's version later if I have the time and inclination.

Feser then goes on to explain why he thinks his version of the argument is actually what Ross intended anyway. Specifically, he addresses what Ross means by saying the calculator is not adding. Now, Ross makes a clear and consistent distinction in his paper between true adding, which he elaborates as carrying out the "pure function" of addition, and what the calculator does, which is only "simulating addition." This is a crucial distinction for him, because his basic claim is that humans can execute pure functions, while any purely physical system cannot.

In my posts I have consistently (I hope) been using "adding" in Ross's first sense. I didn't think it was necessary to spell this out: since I was critiquing Ross's paper, I was using Ross's terminology, except where I explicitly stated otherwise. But to be clear, I will henceforth use ETPFOA ("executing the "pure function" of addition") instead of "adding."

So when I said that Ross denied that the machine was adding, I meant it was not ETPFOA. Feser, on the other hand, wrote,

Ross is not denying, for example, that your pocket calculator is really adding rather than “quadding”....

So how does Feser respond? He quotes Ross's discussion of simulated addition, then writes:

So, Ross plainly does say that there is a sense in which the machine adds -- a sense that involves simulation, analogy, something that is “adding” in the way that what a puppet does is “walking.”  How can that be given what he says in the passage Oerter quotes?  The answer is obvious: The machine “adds” relative to the intentions of the designers and users, just as a puppet “walks” relative to the motions of the puppeteer. The puppet has no power to walk on its own and the machine has no power to do adding (as opposed to “quadding,” say) on its own.  But something from outside the system -- the puppeteer in the one case, the designers and users in the other -- are also part of the larger context, and taken together with the physical properties of the system result in “walking” or “adding” of a sort

In short, Ross says just what I said he says.

Now it is very strange for Feser, who is a professional philosopher, to sweep aside an crucial distinction like this, as if it were unimportant. It is not true that Ross says the machine can add in the ETPFOA sense that both Ross and I are using. It is true that Ross says the machine can do something like adding - but only something that has the name of adding, and gets that name by analogy to ETPFOA, not because it is actually ETPFOAing.

Moreover, I don't see anywhere Ross says that the machine "adds relative to the intentions of the designers and users," as Feser claims. And what exactly is Feser claiming here? That the machine ETPFOAs relative to the intentions of the designers? Or that it only simulates adding relative them?  OK, the machine taken together with the larger context results in addition "of a sort" - but of which sort? Again, Feser glosses over the crucial distinction.

You wouldn't think it possible, but there's actually worse to come. Quoting Feser again:

Oerter insists that I am misunderstanding Ross here.  As we will see in a moment, I am not misunderstanding him at all, but it is important to emphasize that even if I were, that would be completely irrelevant to the question of whether the argument for the immateriality of the intellect that we are debating is sound.  For one thing, and quite obviously, whether or not I have gotten Ross right on some exegetical matter is irrelevant to whether premises (A) and (B) of the argument in question are true, and whether the conclusion (C) follows from them.  So Oerter is, whether he realizes it or not, just changing the subject.  

Later on, he continues in a similar vein:
Evidently the reason Oerter thinks all this is worth spilling pixels over is that he thinks his “Hilda” example shows that Ross is being inconsistent, and he needs for me to have gotten Ross wrong in order to make his “Hilda” example work.  I have already explained, in my previous post, why Ross is not at all being inconsistent.  But even if he were, it wouldn’t matter.  The alleged inconsistency, you’ll recall, is that Ross treats Hilda as adding despite the fact that we can’t tell from her physical properties alone whether she is, whereas he does not treat the machine as adding despite the fact that we can’t tell from its physical properties alone whether it is.  Suppose he really were inconsistent in this way.  How does that show that premise (B) of his argument is false (much less that (A) is false, or that the conclusion doesn’t follow)? 

Answer: It doesn’t.  The most such an inconsistency would show is that Ross needs to clarify what is going on with Hilda that isn’t going on with the machine.  And there are several ways he can do this consistent with the argument.  First, he could say what I would say (and what, as I have shown, he does in fact say himself, despite what Oerter thinks) -- namely that the machine does add in a sense, but just not by virtue of its physical properties alone.  There is perfect consistency here -- both systems, Hilda and the machine, add (albeit in analogous senses), but neither does so in virtue of its physical properties alone.

This is just bizarre. Ed Feser, who revels in pointing out inconsistencies of the naturalists, is arguing that an inconsistency doesn't matter? Nor is this some trivial point of Rossian exegesis, as Feser implies: it's a basic contradiction in Ross's whole scheme.As I pointed out already, the distinction between ETPFOA and simulated adding is crucial to Ross's argument.

The logic of my Hilda example is straightforward. Ross says that humans can ETPFOA. Ross says that  A, B, and C entail that a computer cannot ETPFOA. I claim that A, B, and C are true for Hilda, too. So A, B, and C entail that Hilda cannot ETPFOA.

With this contradiction, the whole argument falls to pieces. Now, you can argue that I am wrong: that A, B, and C are not true of Hilda. Or you can argue that there is some D that I missed that is true of the computer but not true of Hilda. But you can't say this example is irrelevant to the soundness of Ross's argument.

Saturday, October 19, 2013

What Does Ross Say?

Well, no, I'm not making the sort of trivial, "silly" argument that Feser likes to ascribe to me. But before I can clarify this, it is necessary to clarify just what it is that Ross is saying.

Feser writes:

Part of the problem here might be that Oerter is not carefully distinguishing the following two claims:

(1) There just is no fact of the matter, period, about what function a system is computing.

(2) The physical properties of a system by themselves don’t suffice to determine what function it is computing.

Oerter sometimes writes as if what Ross is claiming is (1), but that is not correct.  Ross is not denying, for example, that your pocket calculator is really adding rather than “quadding” (to allude to Kripke’s example).  He is saying that the physical facts about the machine by themselves do not suffice to determine this.  Something more is needed (in this case, the intentions of the designers and users of the calculator). 

What exactly does Ross claim? Here is Ross from his paper:

Adding is not a sequence of outputs; it is summing; whereas if the process were
quadding, all its outputs would be quadditions, whether or not they differed in quantity from additions (before a differentiating point shows up to make the outputs diverge from sums).

For any outputs to be sums, the machine has to add. But the indeterminacy among incompossible functions is to be found in each single case, and therefore in every case. Thus, the machine never adds.

Extending the outputs, even to infinity, is unavailing. If the machine is not really adding in the single case, no matter how many actual outputs seem "right," say, for all even  numbers taken pairwise (see the qualifying comments in notes 7 and 10 about incoherent totalities), had all relevant cases been included, there would have been nonsums. Kripke drew a skeptical conclusion from such facts, that it is indeterminate which function the machine satisfies, and thus "there is no fact of the matter" as to whether it adds or not. He ought to conclude, instead, that it is not adding; that if it is indeterminate (physically and logically, not just epistemically) which function is realized among incompossible functions, none of them is. That follows from the logical requirement, for each such function, that any realization of it must be of it and not of an incompossible one. [emphasis added]
Ross is quite clear: he is not saying (2) at all. Neither is he saying (1). He is saying something stronger than either (1) or (2): the machine does not add - period. It is not that the physical properties of the system alone don't determine what function it is computing, the system isn't actually computing any function at all. "... if it is indeterminate (physically and logically, not just epistemically) which function is realized among incompossible functions, none of them is."

I just don't see how Feser can write "Ross is not denying, for example, that your pocket calculator is really adding rather than “quadding”..." for that is exactly what Ross is denying. 

It is this denial I had in mind when I said Ross couldn't apply the same reasoning to Hilda without denying that Hilda adds, too. But rather than re-visit that argument I will wait for the professor to (I hope) clarify. 

Tuesday, October 15, 2013

Feser and Ross and me

Ed Feser has responded to my complaints about Ross's argument - sort of. Once again, I am flattered that Feser thinks my amateur philosophizing worthy of his attention. I always learn a lot from our exchanges, even if I am not ultimately convinced of his point. He (correctly) diagnoses my confusion between indeterminacy of meaning and physical indeterminism. But that confusion doesn't (I think) invalidate my main point: that Ross's argument never gets him beyond epistemological indeterminacy.

Oddly, Feser doesn't specifically respond to my critcism. Instead, he refers back to his American Catholic Philosophical Quarterly article. But in that article, he doesn't specifically respond to the epistemology objection, either. Here's what he wrote:

Dillard also suggests that Kripke’s point is epistemological rather than metaphysical—that his argument shows at most only that the claim that someone is thinking in accordance with a certain function (such as addition) is underdetermined by the physical evidence, and not that the physical facts are themselves indeterminate. This is odd given that both Kripke and Ross explicitly insist that the points they are respectively making are metaphysical rather than merely epistemological. Indeed, Kripke says that “not even what an omniscient God would know . . . could establish whether I  meant plus or quus,” because for the reasons given above, everything about my past behavior, sensations, and the like is compatible (not just compatible as far as we know, but compatible full stop) with my meaning either plus or quus. Nor does Dillard say anything to show otherwise.
That is, Feser merely states that Ross says that his point is metaphysical, not epistemological. But Feser doesn't give any additional reasons for us to believe that Ross has actually established this. Well, I agree that Ross says that - but I don't think he has established it.

Here's why. Note that Ross's argument is just as valid when talking about what another person is doing when (say) adding. That is, when I am trying to determine whether Hilda is actually adding, or merely simulating adding, all I can do is investigate her physical actions and responses. If Ross's argument is correct, then from a finite amount of data such as these I cannot determine whether Hilda is adding or not. So (if Ross is right) I can never know whether another person is capable of addition.

But note that from the above it doesn't follow that Hilda is not adding. It may be that Hilda is in fact doing something perfectly determinate. I just can't know whether she is or not. So it is clear that Ross's argument doesn't get us past the epistemological.

This point ties in with my second complaint about Ross: the double standard. If I can't say for sure that another person is not adding, then by the same token I cannot say for sure that a machine is not adding.*

In  his article, Feser almost makes the same point. Kripke's original point (if I understand it correctly) was, not only can I not be sure what someone else means when they say something, I cannot even be sure what I mean when I say something. That is, even my own thoughts are indeterminate in meaning. Ross obviously doesn't want this conclusion - his own argument relies on one's own thoughts being determinate. Feser points out that (using Frege's conception of meaning) we cannot infer from the external indeterminacy that there is no internal meaning. He writes:

Frege emphasized that the sense of an expression is not a private psychological entity such as a sensation or mental image, any more than it is something material. Thus he would hardly take an argument to the effect that meaning cannot be fixed either by sensations and mental images or by bodily behavior to establish that there is no determinate meaning at all.

But establishing that there is "no determinate meaning at all" is precisely what Ross needs for his argument. So the argument fails.

* Though it is not directly relevant to the argument, I want to point out that the situation is actually worse with respect to the machine than it is with respect to another person. We can open up the machine, trace its circuits or it mechanism or whatever, and deduce what it will do for a given input. With another person, we can only investigate the physical outputs: we can't open up Hilda's brain and trace its circuitry. Well, not yet, at any rate.

Saturday, October 12, 2013

Ross's Double Standard

Another problem with Ross's argument is the double standard he employs. It's obvious that humans are not nearly as accurate as machines when it comes to computations. But Ross doesn't take this as evidence that humans are not carrying out a pure function. On the contrary, he suggests that mistakes could be evidence that the human is carrying out the function. He writes:

This is not a claim about how many states we can be in. This is a claim about the ability exercised in a single case, the ability to think in a form that is sum-giving for every sum, a definite thought form distinct from every other. When a person has acquired such an ability is not always transparent from successful answers, and it can be exhibited even by mistakes. [Emphasis added.]

But when he talks about machine addition, he counts any error, even a potential error many years in the future, as evidence that the machine doesn't truly add.

This is a blatant double standard. Logically, if a mistake is evidence that X is not performing the function, then that is true whether X is a human or a machine.

Sunday, October 6, 2013

Against Physicalism

Are humans more than just a complicated physical machine? Physicalism is the idea that the physical is "all there is" - everything that exists is either physical or is reducible to something that is physical. Thanks to Ed Feser's blog, I've come across an interesting argument from James Ross that physicalism cannot be true. Ross takes an approach that draws on Kripke, Goodman, and Quine to build a rather astonishing claim about physical systems. Ross's argument is very subtle and worth a close look. If it succeeds, it's truly an astounding accomplishment: one of the great philosophical debates of all times, solved. I don't think it succeeds, and I'm going to try to suggest why not.

Feser summarizes Ross's argument like this:

All formal thinking is determinate.
No physical process is determinate.
Thus, no formal thinking is a physical process.

Specifically, Ross refers to "pure functions" that humans can define but that cannot be implemented by any purely physical system. He gives examples like adding, squaring a number, and the modus ponens of logic.

Now, what makes Ross think that a physical system cannot add? Of course he knows that mechanical devices and computers are capable of performing sums, but he says they are only simulating addition, not truly adding. He writes:

 Whatever the discriminable features of a physical process may be, there will always be a pair of incompatible predicates, each as empirically adequate as the other, to name a function the exhibited data or process "satisfies." That condition holds for any finite actual
"outputs," no matter how many. That is a feature of physical process itself, of change. There is nothing about a physical process, or any repetitions of it, to block it from being a case of incompossible forms ("functions"), if it could be a case of any pure form at all. That is because the differentiating point, the point where the behavioral outputs diverge to manifest different functions, can lie beyond the actual, even if the actual should be infinite; e.g., it could lie in what the thing would have done, had things been otherwise in certain ways. For instance, if the function is x(*)y = (x + y, if y < 10^40 years, = x + y + 1, otherwise), the differentiating output would lie beyond the conjectured life of the universe.

Now, I can go along with Ross as far as the epistemological aspect of his conclusion: no matter how many input-output pairs we examine, we can never know what function is being computed. But Ross claims much more: he says physical systems are not just epistemologically indeterminate but "physically and logically" indeterminate, too. That is, it's not just that we can't know what function the machine is computing, but there really is no fact of the matter about what the output will be until it actually happens.

The problem is, the argument Ross gives is not up to the task of proving that claim.

First of all, what does Ross mean by "empirically adequate"? He is not using this in the sense of van Fraasen, for whom empirical adequacy means agreement, not just with all past observations, but with all possible observations. For Ross explicitly mentions a "differentiation point", possibly at some remote future time, at which the outcomes disagree. Nor does he mean "agreement with all future observations", for the same reason. So he must mean merely "agreement with all past observations."

But having two hypotheses that agree with all past observations is not enough to tell us that the physical system is actually (physically) indeterminate. It only says that our information is insufficient to distinguish between the two.

Another example Ross gives is the problem of determining a function, knowing only a finite number of data points. He (correctly) points out that there is an infinity of curves that will agree on those finite data. But this just says we don't know what the function is that produced the data. It doesn't follow that there is no such function at all. But that's what Ross needs for his conclusion that physical systems are not just epistemically indeterminate, but physically indeterminate.  

Ross's other arguments draw on Goodman's and Quine's work. These, too, also only reach as far as epistemology. Goodman's grue problem suggests that we can never know for sure whether we are inducting on the right categories. But it is a long way from that epistemological claim to the claim that there are no correct categories for induction to work on. Duhem's claim about undertermination says only that we can't know what part of whole complex of assumptions, theories, and practices is at fault when an experiment disagrees with theory. Again, this is only an epistemological claim. True, Quine tried to extend this uncertainty to the whole realm of human knowledge - but this extension hardly helps Ross's claim that humans can add, employ modus ponens, etc. Thus,none of Ross's arguments, either in the article or in his book, Thought and World, take us beyond epistemological indeterminacy.

I have to say it is exceedingly odd to see Feser defending physical indeterminism here. In our discussions of quantum mechanics and causation he argued strenuously that there is no such thing as physical indeterminism - not even in the case of quantum mechanics (where nearly all physicists accept fundamental indeterminism). So I'm wondering how Feser can square real, physical and logical indeterminism with the principle of causality.