Wesley Cooper

This link  is from Alastair Medford; the image is from Matthew Benesch.

See also Steve Reiter’s comment under the post for Copeland’s “Are we computers?” chapter.

TERM PAPER REMINDER: IT’S DUE DECEMBER 7TH. IF YOU WANT ME TO COMMENT BRIEFLY ON A ROUGH DRAFT, GIVE ME AT LEAST THREE DAYS.

FINAL EXAMINATION REMINDER: IT TAKES PLACE THURSDAY, DECEMBER 10TH, AT 2PM. YOU WILL HAVE TWO HOURS. NO BOOKS OR NOTES, PLEASE.

LOOKING FOR A KILLER RESEARCH FOCUS FOR YOUR TERM PAPER? YOU MIGHT PERUSE WHAT’S ON OFFER AT DAVID CHALMERS’ CATALOG OF ONLINE PAPERS. TRY THE LINK TO `PHILOSOPHY OF ARTIFICIAL INTELLIGENCE’, FOR EXAMPLE.

“Other times are just special cases of other universes.”

The French singer Francis Cabrel sings about “the speed at which time passes” (”La robe et l’échelle“). Deutsch is the wise guy who asks, knowing that there is no good answer, “And what speed is that?”

• The A-series and the B-series

The case for a language of thought (”Mentalese”)

Angela Kostiuk found this take on the multiverse.

Erica and Ashton reported in comments to this site that the most recent Searle video wasn’t working. This raises the question why no one else did so?? Anyway, it should be working now. Its permissions weren’t set correctly on the Arts server.

A brief review of Deutsh’s chapter on mathematics, including some term paper suggestions.

1. The strong symbol system hypothesis [Pylyshyn]
2. Hardware versus wetware [McCulloch & Pitts]
3. Goodbye, von Neumann [von Neumann]
4. Putting meaning into meat [Fodor]
5. Believing what you don’t believe [Pylyshyn]
6. Productivity and systematicity [McGinn]
7. Evaluating the arguments [Biederman]
8. The meaning of `computer’ [Searle]

Here’s Searle lecturing on whether the brain is a digital computer (i.e., SSSH, or what Searle calls `cognitivism’).

• Read the rest of this entry »

Rene Descartes, Discourse on Method (Discours de la methode pour bien conduire sa raison, & chercher la verité dans les sciences)

==========

We’ll start today with a ten-minute talk by Dave Adams on Ch 10. And here’s some background information he has collected for us  about Shor’s algorithm.

In Chapter 2, Descartes sets out his four rules of proof.

The first was never to accept anything for true which I did not clearly know to be such; that is to say, carefully to avoid precipitancy and prejudice, and to comprise nothing more in my judgement than what was presented to my mind so clearly and distinctly as to exclude all ground of doubt.

The second, to divide each of the difficulties under examination into as many parts as possible, and as might be necessary for its adequate solution.

The third, to conduct my thoughts in such order that, by commencing with objects the simplest and easiest to know, I might ascend by little and little, and, as it were, step by step, to the knowledge of the more complex; assigning in thought a certain order even to those objects which in their own nature do not stand in a relation of antecedence and sequence.

And the last, in every case to make enumerations so complete, and reviews so general, that I might be assured that nothing was omitted.

==========

Descartes represents a tradition that Deutsch traces back to Aristotle, according to which a proof is a sequence of statements that obey rules of inference. This is the idea that a proof is a type of object. Deutsch argues for a view of proof as a process. Proof-as-process becomes inevitable, and irreducible to proof-as-object, in the context of computations that require quantum computation. Here is the key passage (page 251):

Now, consider some mathematical calculation that is intractable on all classical computers, but suppose that a quantum computer can easily perform it using interference between, say, 10⁵⁰⁰ universes. To make the point more clearly, let the calculation be such that the answer (unlike the result of factorization) cannot be tractably verified once we have it. The process of programming a quantum computer to perform such a computation, running the program and obtaining a result, constitutes a proof that the mathematical calculation has that particular result. But now there is no way of keeping a record of everything that happened during the proof process, because most of it happened in other universes, and measuring the computational state would alter the interference properties and so invalidate the proof. So creating an old-fashioned proof object would be infeasible; moreover, there is not remotely enough material in the universe as we know it to make such an object, since there would be vastly more steps in the proof than there are atoms in the known universe. This example shows that because of the possibility of quantum computation, the two notions of proof are not equivalent. The intuition of a proof as an object does not capture all the ways in which a mathematical statement may in reality be proved.

Read the rest of this entry »

Class canceled Monday (instructor’s cold) and Wednesday (Remembrance Day)

Before we meet next on Friday, November 13th, you should have read about half of Copeland’s Chapter 9, as well as Chapter 10 in Deutsch’s book.

Henri Matisse, “Fenêtre Ouverte” (1905)

I’m handing out midterms today. If you’re absent from class, you’ll have to wait until next Friday, I’m afraid.

Review of Copeland’s chapter on Freedom

• Think of compatibilism (soft determinism) and libertarianism (indeterminism) as two extremes, represented by Hobbes and Copeland, at one extreme, and Descartes and Searle, at the other. There are problems at each pole: Many think that freedom goes deeper than compatibilism allows, and libertarianism has a hard time separting free action from arbitrary, random action.
• Are there alternatives to these extremes? Think of Nagel’s “romantic” view that we are bound to think of ourselves and the world from two incompatible points of view, subjective and objective. That’s one alternative. Think of Deutsch’s multiverse solution: One could have done otherwise means One did to otherwise in other worlds. (Deutsch elaborates on this a little bit later in the book, but it must be said that his alternative is sketchy.)

Review of Copeland on Consciousness

• Think of materialism and dualism as two extremes. Define materialism as committed to an account of mind exclusively by reference to “third-person facts” typified by current natural science. Define dualism as Cartesian substance dualism and variants on it, including not only “parallel substances” but also “property dualism” (one substance that is material, but it “gives off” non-physical mental properties) — Huxley’s epiphenomenalism is an example.
• Are there alternatives to these extremes? Searle offers an alternative which demands that subjective physical facts be recognized as a part of the natural sciences. (”Physics” in his sense includes objective physics, defined by the third-person point of view, and also subjective physics, defined by a first-person mode of access.). Another alternative is Colin McGinn’s “mysterianism“, which argues that the relationship between mind and body is cognitively closed to humanity: our species doesn’t  have the right kind of mind to comprehend the “world knot”, even though the relationship is presumably a natural one that is in principle available to some continuation of the natural sciences, a continuation that is beyond us.

• Deutsch’s chapter on Life: The essential point to grasp in this chapter is that life is to be understood in Darwinian evolutionary theory, especially as developed by Richard Dawkins, and that the defining features of life — of evolving replicators — are best explained by the multiverse: by life’s being a an organized cross-world structure. Life (and knowledge, and freedom, etc.) are phenomena that support counterfactuals: This DNA (which hasn’t replicated in our universe) would replicate under the appropriate circumstances. Counterfactuals are puzzling to philosophers. What makes them true? MWI offers one answer: other worlds make them true.
• Deutsch’s chapter on Quantum Computing: The essential idea here is tractability. Things get computed in nature. How is this possible? Maybe some fancy architecture of a USS (UTM) is sufficient to explain how the brain is able to process information sufficiently fast to keep us alive, but how does Shor’s algorithm get computed in nature? Factorization of very large numbers seems intractable for classical computing, but Shor’s algorithm renders it tractable. How does it do that? Deutsh thinks that quantum computing banishes the specter of intractability in such cases.
• I’ve invited Dave Adams to talk to us about how Shor’s algorithm works on the formal side.
• I’m cancelling class on Monday, and the University is cancelling class on Wednesday in observance of Remembrance Day. So: Start reading Chapter 9 in Copeland (”Are we computers”). You know what it’s about! Also start Chapter 10 in Deutsch (”The Nature of Mathematics”). This chapter shows how uncompromising his physicalism is. Also, in lieu of class on Monday, please listen to Deutsch’s introductory video on QM. You should understand the first few minutes, even if, like me, you start listening to it as background music later on.

A universal quantum computer within a decade?

That’s what Deutsch is now saying. He’s emboldened by recent research in quantum cluster computation.

We saw in Ch 6 of FoR (”Universality and the Limits of Computation”) that the universal computer that figures in the Turing principle isn’t limited to the repertoire of a universal Turing machine. Ch 9, “Quantum Computers”, makes explicit the need for a UQC’s expanded repertoire in order to deal with tractability issues that are resolved by quantum computing. Deutsch’s primary example is Shor’s algorithm, which he regards as a proof of the multiverse comparable to the Chapter 2 proof. In each case the proof requires a realist (non-instrumentalist) view of science: Photons move in the slit experiments “as if” they were colliding with “shadow photons”, and the existence of such photons is the best explanation for what appears to happen in those experiments. Similarly, an explanation of how Shor’s algorithm works would have to posit vastly more vehicles of information (segments of tape on a Turing machine) than the number of atoms in the universe, and the existence of collaborating universes is the best explanation for how the algorithm works despite the absence in this world of the necessary computational resources.

• Dennett’s “Freedom Evolves”, Part 4
• Participation sheets on Friday, please
• I have a cold. If it gets worse, I’ll cancel class on Monday to take full advantage of the Remembrance Day break in order to recuperate. I’ll post an announcement here over the weekend, so please check here before coming to class on Monday.

• Read the rest of this entry »

Is there a philosophical problem about zombies? 

• Reading for this week: Ch 8 of Copeland, “Consciousness”, and Ch 9 of Deutsch, “Quantum Computers”
• On Friday we’ll resume Participation sheets, and we’ll do a crossword puzzle. If my cold doesn’t slow me down, I should be able to return the midterm on Friday as well. I’ll venture a couple of points about the midterms I’ve read so far.

1. Some people saw that for Deutsch the universal quantum computer has a broader repertoire than a universal Turing machine. The UQC goes beyond the “mathematician’s-eye-on-tape” paradigm of the UTM.
2. Some people saw that the UQC that provides the foundations for computing science must be physical, not abstract, and it must be able to render all physical possibilities, including our experience of the world. It does what Turing aspired to do, explaining everything that can be computed “in nature”.

• A bit of review from Ch 7, “Freedom”: van Inwagen’s β (See page 159):

1. NA
2. N(A⊃B)
3. therefore NB

Copeland: “For short, think of NA as saying that A’s truth is not up to you (or me or anyone else) and never was.”

Consider the following instantiation of line 2: It is not up to you whether there are causal conditions A, antecedent to your choice, which are sufficient for your doing B. There are such conditions (line 1). Therefore it’s not up to you whether you do B (you don’t act freely). We saw the other day Dennett’s way out: It’s up to you whether you do B, in the sense that if you hadn’t wanted to do B, you wouldn’t have done so. Line 2 is true. Here’s Searle’s way out: Just as circumstances were, including your wants, you could have done otherwise. Line 2 is false.

• Here are some notes about Copeland’s Ch 8, “Consciousness”.
• Two points about Ryan’s video (comment, “Freedom”):

1. The video presupposes a “collapse” interpretation of QM, whereas Deutsch is presenting a “no-collapse” interpretation.
2. The possible worlds referred to in the video are possible continuations of this world. The video presupposes a “one-world” view with lots of dimensions (ten, I believe) and with lots of possibilities (possible worlds, not actual worlds), whereas of course Deutsch’s is a many-worlds view: the possible worlds  are actual worlds, not unrealized possibilities after the collapse of the wave function.

• Dan Dennett, “Freedom Evolves”, Part 3

• Here is an anecdote about the meaning of life from Robert Nozick’s book, Philosophical Explanations:

The question of what meaning life has, or can have, is of utmost importance to us. So heavily is it laden with our emotion and aspiration that we camouflage our vulnerability with jokes about seeking for the meaning or purpose of life: A person travels for many days to the Himalayas to seek the word of an Indian holy man meditating in an isolated cave. Tired from his journey, but eager and expectant that his quest is about to reach fulfillment, he asks the sage, “What is the meaning of life?” After a long pause, the sage opens his eyes and says, “Life is a fountain.” “What do you mean, life is a fountain?” barks the questioner. “I have just traveled thousands of miles to hear your words, and all you have to tell me is that? That’s ridiculous.” The sage then looks up from the floor of the cave and says, “You mean it’s not a fountain?” In a variant of the story, he replies, “So it’s not a fountain.”

• Some notes for Friday’s discussion of Chapter 8 in FoR, “Life”

• Here’s another undergraduate journal that’s calling for papers.
• And here’s a link to The Philosophical Lexicon, as promised. The verb ‘turing’ is introduced: “I’ve been turing on my lecture notes.” I’m capable of turing, but dworking is quite beyond me.
• If a Lexicon entry is relevant to your term paper, feel free to use it discretely — maybe in a footnote.
• Looking through the Participation sheets, I’ve noticed several complaints that the level of chatter in class is preventing people from hearing lectures and student comments/questions. Please be respectful of others by saving chatter for after class.