Reality Conditions

Friday, July 21, 2006

Next week schedule: either Hiatus or Conference Liveblogging

As I mentioned a couple of posts ago, I'm heading off to Berlin for the Eleventh Marcel Grossmann Meeting, a huge conference where all the reseach areas in GR (classical and quantum) will be represented. Depending on how easily can I access Internet, and how much free time do I have, I might do some conference liveblogging. So keep an eye on the blog! Aside from that possibility, normal posting will come back by the 1st or 2nd of August, probably with a summary of conference highlights.

Wednesday, July 19, 2006

A Psychology Experiment

I took part today in a psychology experiment at university, and thought it would be interesting to describe it here.

The session in which I participated had about 12-15 participants. (There were several other sessions at other times as well). Each of us had to answer 6 question sheets, independently of all the others and without knowing anything about their answers (with a couple of exceptions I'll get to). Each question sheet would decide a payoff (between £0 and £20 in the lowest and greatest possibilities) and at the end of the session (which lasted for 1 hour) we rolled a dice and recieved the payoff according to that sheet, plus £10 just for participation. The question sheets were in many cases versions of classic experiments I knew about, like the Prisoner's Dilemma and the Ultimatum Game.

1) The first sheet obviously had the purpose of measuring risk-aversion. There were ten cases, and for each case two options to choose between. Option A always involved a payoff of either £4 or £5; option B always involved a payoff of either £9.60 or £0.25 (if I remember the amounts correctly). The probabilities varied between the ten cases: Case 1 was a decision between £4 certain against £9.60 with probability 0.1 and £0.25 with probability 0.9; Case 2 was a decision between £4 with probability 0.9 and £5 with probability 0.1 against £9,60 with probability 0.2 and £0.25 with probability 0.8; and so on until case 10 was an almost certain £5 against a certain £9.60. Obviously in the first cases one must choose A, and in the last ones B; there is an point in the middle where the mathematical expectated gain of B becomes larger, but risk-adverse persons will wait more than that before switching, for fear of the possibility of £0.25. I was tempted to take the mathematically "correct" choice just for the sake of it, but finally my risk-aversion won over me and I marked option A for all cases which had probability less than 0.7 for the £9.60. (If the dice at the end rolled 1, the payoff would be chosen by two more randomizations -one to choose which of the ten cases applied and one to choose the payoff according to the case's probabilities).

2) This was an interesting asymmetrical variation on the Prisoner's Dilemma. Half of the participants were assigned to be Senders, the other half Recievers. Each Sender had £4 and had to decide how much of it to send to a randomly paired Reciever. The Reciever would recieve that amount multiplied by 3, and could choose to send back any amount to the Sender. So for example if I choose to send £3, my partner (which, like I, remains anonymous) recieves £9 and if he chooses to send back £4, we will get each a payoff of £5 (I get the £4 plus the £1 I kept at the beginning). I was a Sender, and the choice was to "play sure" and not send anything (I get £4 certain) or to be nice and trustful sending money that will be multiplied, hoping that my partner will be grateful and reward me sending back more than the mere £4. I choose to be extremely "nice" and send the whole £4, risking to lose it all (nothing forces my partner to send back anything; we will never even know who each other was) but trusting that happy at recieving £12 the other person would send back, if not £6 for a fair share, at least £5 to make it worth for me. We Senders also had to fill in a form which amount we expected to recieve back; I wrote £5. Unfortunately my dice didn't fall on 2, so I will never know what the other person did.

3) This one was a simple Ultimatum Game. Senders had £10, and could offer any fraction of the amount to Recievers. Recievers had to accept, in which case the amount was shared as the Sender had proposed, or decline, in which case nobody got anything. Obviously a "rational" reciever would accept any amount, which is always better than nothing; but in practice if offered a low share people will refuse it out of spite to make the greedy Sender lose his part as well. I was a Sender again, and offered £4, which was the lowest amount I was sure anybody would accept.

4) This was a Future Discount experiment. We had again 10 cases, and for each case we had to choose option A or B. Option A was always recieving £10 within 2 weeks, and option B was recieving within 8 weeks an amount that progressed from £10.25 in Case 1 to... I can't remember how much, but probably as much as £20, for Case 2. I didn't care too much for the amounts and just circled option B in all cases! I'm not in a pressing need for money, and I guess the subjective probability I assign to suddenly needing ten extra pounds between the 2 weeks time and the 8 weeks time is significantly lower than 2.5%.

5) An Ultimatum Dilemma but without any option for the reciever. The sender just decides at will how to split £10, and the reciever has to accept it. Previously the reciever writes in his sheet how much he expects to recieve. (I was a reciever here, and I expected to recieve a paltry £1. Fortunately I didn't roll a 5 so this low confidence in the unadultered altruism of my fellows was not tested).

6) A Prisoner's Dilemma. Each of us was playing with a randomly slected (and anonymous) partner, and had to choose whether to "contribute" £0, £1, £2, £3 or £4 to a deal. The payoffs were escalated in the expected way, with the lower contributions always dominating the higher ones. For example, payoff if both contributed £0 was £4 for each, if one contributed £0 and the other one £4 it was £6 for the "defecter" and £3 for the "cooperator" and if both contributed £4 it was £5.30 for each. My decision, surely influenciated by my many readings of accounts that put the "Cooperation or Defection" dilemma at the very centre of Ethics, was to cooperate with £4 to keep my self-image high. I rolled a 6 at the end of the session, found that my partner had done almost as well as I did contributing £3, and I won £4.80.

So that was it. As to the purpose of the experiment (and its global results) I will only learn them when a paper is written (we were promised to be informed when this happens). As I thought that each of this particular experiments had been done thousands of times already, my idea is that the study aims at finding correlations -e.g between being risk averse and being a Defector. Any other ideas...? Any comments or violent disagreements with my decisions...?

Tuesday, July 18, 2006

Preparing transparencies

I have been writing up my transparencies for a talk on my work I will give next week at the Eleventh Marcel Grossmann Meeting. You can read the abstract here; you will see it is the same material covered in my recent paper, plus an extension to de Sitter space I have been working in.

I always use hand-written transparencies instead of printed transparencies or PowerPoint or similar presentation programs. The reason is simple laziness -writting transparencies is much faster, Unfortunately, my handwriting is not only atrocious but also very small. Added to this, my natural tendency is to write complete, grammatical sentences instead of just bulletpoints and the like. So my transparencies end up being full of ugly, densely-packed lines of text and equations. My speech sticks closely to what is written so it is not that difficult to follow -but after seeing my last talk my supervisor suggested that I should try to make less-cluttered transparencies.

The problem is I can't. I may try to write larger -but unconsciously I always revert fast to tiny letters. (Amateur psychologists please refrain from commenting). And a transparency with just three or four lines of text and math in very small handwritting looks ridiculous, so the temptation to go on writing and fill it is large.

So what I did at the end is to use superposed transparencies. For those transparencies that could be "broken" in a natural way I wrote the upper half of one transparency, and the lower half of the next one. In the talk I will show first the first transparency, talk about it, and then place the second one on top of it. Hopefully, the audience will have time for reading each part without being intimidated by a transparency with so many lines of text.

I borrowed the trick from my supervisor, who uses it mostly for the kind of flashy effects you can use PowerPoint to do; for example once he had a transparency with the classical Poisson brackets of a theory, said "And now to quantization", and put on top of it a transparency with "hats" ands "i hbar" in the right places to create quantum conmutation relations. But it's not something I've seen people do often; I guess those who like that kind of effect go directly for a presentation software.

I am interested in hearing, has anyone met the same problems I have? More generally, what are your difficulties and strategies when preparing talks?

Sunday, July 16, 2006

More Links

* Sigfpe continues the discussion on the reality (?) of particles in QFT.

* Dimitri Terryn is blogging an introduction to string theory.

* Scott Aaronson has a Best Anthropicism Contest, where an "anthopicism" is an application of the Anthropic Principle (intended to be self-referential, slightly tautological, and not very serious). My submission was: "Why is the Anthropic Principle silly? Because if it weren't, I wouldn't be writing this comment making fun of it."

* The discussion about Tibbles and ontology continues at Siris. (Update: more here.)

* David Plotz is blogging the Bible at Slate. From the point of view of a "proud but not terribly observant Jew", who has never read the Bible nor studied scholarly commentaries on it, he is just reading the book innocently and blogging his impressions. A funny and sometimes insightful read. I must confess I never went through the whole Bible, though I attempted it twice in my life.

* Via Positive Liberty, I found this terrifying story about the persecution suffered by an atheist family in Oklahoma. I have wrote nice and conciliatory posts about how science and religion need not clash, but that doesn't mean that these stories don't get me as incensed as your average Pharyngula reader. Specially if you add other similarly disheartening stories like the persecuted Jewish family in Delaware and Rob Knop's encounter with creationists. What is wrong with America?

* Of course you could rather ask what is wrong with the world. Sigh.

Saturday, July 15, 2006

The Essentials of Languages

I had found this page long ago, but forgot about it until seeing it linked in The Valve now. It is a collection of funny Essentialist Explanations about languages. Some of my favourites:

English is essentially Anglo-Saxon with all the cool bits taken out.

English is essentially Pictish that was attacked out of nowhere by Angles cohabiting with Teutons who were done in by a drunk bunch of Vikings masquerading as Frenchmen who insisted they spoke Latin and Greek but lacked the Arabic in which to convey that.

Inglish iz issenshali a langwidje dhat, wen rittun fonetkli, iz ilejibul tu netiv spikerz.

Spanish is essentially Italian spoken by Arabs.

Argentinean is essentially Italian spoken so that other South Americans can catch on.

Classical Latin is essentially an artificial language devised to make the vulgar Roman aristocracy sound intelligent.

Franche est essentialement englaishe ouithe les endinges funnies et lottes de vowelles et les adjectifs en alle les places ronges.

Brazilian is essentially Spanish spoken by Portuguese hot babes with rhythm.

Brazilian is essentially a conlang created by people who wanted to have sex all the time, but still be able to talk about everyday things.

Orkish is essentially Klingon as spoken by Orcs.

Wednesday, July 12, 2006

On Cats and Mats and Parts and Ontology

Brandon has a recent post presenting a philosophical puzzle. Suppose you have a cat, Tibbles, sitting on a mat. Define "Tibbs" to be the part of Tibbles including everything but its tail. It would seem that if Tibbles lost its tale, it would become Tibbs, and it would continue to be a cat; so Tibbs is a cat just as Tibbles is. Are they two different cats?

If you say yes, you are commited to saying that now there are really two cats on the mat, even though it seems there is only one. Moreover, by repeating the argument with other body parts instead of the tail (as small as you wish, even atoms) you can prove there are an enormous number of cats on the mat, where you can see only one; a bizarre conclusion. But if you say no, that Tibbs and Tibbles are the same cat, aren’t you contradicting yourself? After all, one has a tail and one hasn't; how can they be identical?

The technical name for this puzzle is The Problem of the Many, and it is discussed in this SEP entry. Brandon goves a summary of different solutions to it, none of them fully satisfactory. There are many similar ontological puzzles that philosophers delight on; for example:

The paradox of composition: Take a lump of clay and make a statue out of it. Are there now two different things, a lump of clay and a statue? Of course not, there is only one: the lump of clay is the statue now. But how can the lump be identical to the statue if they have different properties (e.g. one existed since long before the other one)? After all, must not identical things have all the same properties?

The problem of temporal parts: Think of a table at two different times, for example yesterday and today. Is the table of yesterday the same thing as the table of today? We would like to say yes (otherwise there exists a new and different table at any new instant of time) but how can they be if they have different properties (for example different things on it)? Perhaps we should say that the table-of-yesterday and the table-of-today are just two "temporal parts" of a unique four-dimensional objet which is the "word-tube" of the table. But then the two tables are not the same thing after all, just different parts of the same thing (and that same thing is a weird 4D object nobody would dream of speaking about outside physics or philosophy…)

I’m sure that with some ingenuity you can invent other puzzles of the same kind. The question I want to make is, are these questions deep? Does pondering them tell us anything about the Nature and Ultimate Structure of Reality, or whatever it is metaphysics is supposed to aim at discovering?

I’m sure many of my physicist readers (perhaps also my non-physicist ones) share my natural intuition about the answer: No! These are just trivial problems about finding the best way to talk about situations which are not really problematic at all. Philosophers that waste their time puzzling about them, are, well… wasting their time.

However, we must be careful not to be too dismissive (lest we should be accused of arrogance) without providing an explanation of why these are really non-problems. And babbling some positivistic or Popperian points about solutions to these problems not being testable will not do. There are many properly philosophical problems which do not seem, at least to me, as trivial and unreal as these ontological puzzles. Just to mention two among many: the mind-body problem, and the tangle of problems relating causation, determinism and free will. Can we give an account that distinguishes "real" philosophical problems from "unreal" ones?

A possibility that appeals to me is the broadly pragmatist stance that most philosophical problems consist in discussions about the best way to talk about some aspect of reality (the best conceptual scheme, if you please) where "best" means something like most prectically convenient, involving less tension with frames used in other areas, and so forth. The difference between "real" and "unreal" problems would then be that in the "real" ones the choice of way of talking/thinking about some things is intertwined with and affects many other areas of thought. For example, deciding whether determinism is compatible with free will is, by itself, just a "trivial" semantical question on how to define "free will"; but because our idea of freedom is connected with things of practical importance such as moral and legal responsibility, the problem of finding the best frame of concepts to talk about these things is a "deep" one. By contrast, the question of whether Tibbs is a different cat than Tibbles is one that has no practical significance whatsoever. And I don’t mean "practical" in a vulgar and utilitarian way, but in a broad way that refers to any consequences for our thoughts on other areas. The Problem of the Many, and similar ontological puzzles, seem to me to stand in "isolation" from scientific, legal, moral or other concerns. That it what makes them seem unreal. A rich philosophical problem, like the mind-body problem, is such because its core conceptual/pragmatical issue ("What is the best way of talking about persons, their thoughts and their brains?") is intertwined with and deeply affects our view of sciences like psychology, neurology, and artificial intelligence, and legal and moral questions about many practical issues (e.g. animal rights).

Brandon does acknowledge by the end of his post that the problem would be unreal if it were not related to other concerns:

If a lot of this sounds like word-chopping, you're almost right. It certainly does seem like a lot of the mereological literature does get into word-chopping, and weird word-chopping at that. But it's not purely verbal, because it matters a great deal to the way we reason about identity, parts, and wholes…Which position you take can change the sort of objections you can make to other positions… it can change the way you think proper parts are related to wholes.

But I confess I don't see finding the best logically precise way of talking about parts and wholes something that "matters a great deal". Does it matter for practical, or for theoretical purposes? Not for practical ones; our ordinary language is good enough for describing things like parts of cats; I am not aware of practical concerns that require a more logically precise conceptualisation (as for example, a discussion about abortion may require a more precise conceptualisation of personhood than our unreflective one). But also not for theoretical purposes; because if one has the philosophical goal of finding a sort of "ultimate vocabulary", sharp and precise, which reflects in some sense the structure of the world, then one should not use in the discussion ordinary things like cats and tables One should make first an analysis of our deepest scientific theories, like Quantum Field Theory or perhaps String Theory, and design a conceptual frame that fits well with them. Of course, ordinary notions of "objects", "parts", "properties", "time" and so on would probably not map at all into the mathematical structure of these theories, and so the ontological puzzles I started with could perhaps not even be stated, let alone solved, by taking this route. They would be just riddles about how to make more precise an ordinary language we don't need to make more precise, either for theoretical or practical purposes. (I'm writing of course from a completely secular standpoint, so I pass over Brandon's mention of the structure of the Holy Trinity as an application of the ontology of parts and wholes).

Now I should say that not all philosophical problems seem to me to be pragmatical/conceptual. Some of them seem to me as straightforwardly factual as any scientific question. God exists or does not exist; there is a soul distinct from the body or there is not. (It is only when Cartesian dualism is ruled out and we shuffle around the merits of property dualism, nonreductive materialism, functionalism and eliminative materialism that the mind-body problem starts looking "conceptual" to me). And I still regard scientific questions, save perhaps for borderline cases like the interpretation of quantum mechanics, as factual and not pragmatical. But now the natural question would be, of course, how to distinguish "factual" questions from others. Quine made a convincing case that there was no deep distinction between what positivists like Carnap saw as factual questions and those they saw as philosophical/conceptual ones to be decided pragmatically. Many analytical philosophers who succeeded him interpreted that "ontological" questions were as factual and "real" as scientific ones and started to discuss them with complete earnestness, something I have criticized above. Can my position escape swinging to the other extreme and saying with Rorty that there is no such thing as "factual truth" and that all problems are just pragmatical ones about the best way of talking in a given situation? I hope so, because I have strong instinctive leanings towards scientific realism; but I have not yet figured out how. What I have said implies a rejection of "naive realism" in ontology, the idea that questions such as "do the parts of an object exist as objects?" is a "real" one that demands an answer. But in absence of a sharp criterion distinguishing science and philosophy, facts and conceptualisations, how can I treat the question "do electrons exist?" as a "real" one as I would like to?

Friday, July 07, 2006

Ideas to title your paper

If you have some time to spare, go and check Bee's list of stupid paper titles. In a comment I submitted a few favourites of mine, like:

Can dark energy evolve to the phantom?

which sounds straight from a Star Wars movie, or

Local pancake defeats axis of evil

which sounds plain surrealistic.

In a more serious vein, Bee has also posted a list of her Top Ten Unsolved Questions in Theoretical Physics.

Thursday, July 06, 2006

Book Reviewing

I have finished reading all the books I mentioned in this post, along with several others. Reviews of varying length and detail follow:

1) Richard Dawkins, The Ancestors' Tale. I had bought it because I reckoned a complete story of the evolution of all major life forms on Earth written by Dawkins to be unmissable, but at the same time I feared that the level of detail about particular animals and plants could well bore me; that is what putted me off about biology in high school. I should have known better; Dawkins never writes a dull paragraph and can explain in exciting ways how the evolution of a particular creature exemplifies general biological principles. A must read.

2, 3) Philip Pullman, The Subtle Knife and The Amber Spyglass. The second and third part of Pullman's fantasy trilogy, His Dark Materials, hooked me as no book had done in a very long time -a little surprising because the first volume, Northern Lights, had failed to impress me, and in retrospect I can't point to any definite things making the other volumes better than it. I just couldn't stop reading them! They take place in a "multiverse", moving between our universe and many other parallel ones whose description displays a rich imagination, following the adventures of children Lyra and Will as they become unwittingly the centerpieces of a Miltonian cosmic drama -nothing less than the rebellion of an alliance of men, angels and other creatures from many universes against a tyrannical God. There are many clever details that make the story less "fantastic" and more "science-fictional", adding realism to it; among them references to dark matter and quantum entanglement, and a wonderful description of alien creatures in another universe that shows such insight into symbiotical evolution that Dawkins cites it approvingly in The Ancestors' Tale. As criticism I could say that the ending is a bit unsatisfactory, leaving many things unexplained and adding many others "out of nowhere" just to create a tragic dilemma that looks artificially contrived, and also that the anti-religious rethoric is too heavy-handed at points and detracts from the narration (although no more than the pro-religious rethoric in Chronicles of Narnia by Pullman's bête noire C.S. Lewis, which show also much less imagination in my opinion).

4) Susanna Clarke, Jonathan Strange and Mr Norrell. This one took me over a week to read, in contrast to three days for Pullman's books. It is a strange book, delightful and hugely enjoyable by parts, but also very maddengly long and digressive at others, and perhaps suffers from trying to be too many things at the same time. It is set in an England in an early 19th century much like the one we know -the Duke of Wellington is fighting Napoleon, King George is in a madhouse, and Lord Byron is writing his poems- but with the difference that the past of this England is one in which in medieval times Magic existed and worked, roads communicated England with Faery were open, and a magician called the Raven King had reigned over Northern England for 300 years. All that is now in the past, and magic has become only a scholarly and theoretical matter -until one Mr Norrell discovers how to make "practical magic" again, soon followed by another magician called Jonathan Strange. Norrell is middle-aged, cautious, selfish, and petty; Strange is young, daring, and romantic. Together they start using Magic for the practical matters the Government commands them to -mostly aiding in the war against the French- but soon the re-awaking of magic breaks out of control as the clash between both magicians becomes inevitable, while a mischevious fairy begins playing tricks of his own...

The novel is written in a very 19th century style, reminiscent of Jane Austen, but with many amusingly digressive and scholarly footnotes on details of magical history. The characters are well-drawn, the universe of the story is extremly well concieved and described, succeeding in making its alternate past believable, and many incidents are really very funny -I laughed out loud at a couple of times. But the novel is also very long, has too many storylines that are barely kept together (particularly in the second half). I found myself liking the parts the were Austenian comedy of manners and comical application of magic to pedestrian uses, and disliking the parts related to the fairy king and his magical world; his actions were too arbitrary to be interesting.

5) Frederick Forsythe, The Day of the Jackal. A classic thriller that was my choice for plane-reading in my trip to Buenos Aires. The gripping tale of the attempted murder of president de Gaulle served well its purpose of keeping me well-entretained during the flight. Forsythe is a favourite author for me in the thriller genre, although in his latest books right-wing ranting mixes too often with the narration.

6) Fernando Savater, La infancia recuperada. The story of my relation with this book, called Childhood Regained in English, is a strange one. It is a collection of essays by a Spanish philosopher on the favourite books and authors of his childhood, that combine nostalgic indulgence with mature critical reading. I read it borrowed from a friend at age 15, and was amazed to see a philosopher discuss all my favourite authors: Jules Verne, Robert Louis Stevenson, Emilio Salgari*, Daniel Defoe, Arthur Conan Doyle, Agatha Christie, Edgar Allan Poe, H.G. Wells, J.R.R. Tolkien... It felt like discovering a kindred soul. I had never forgotten the book, and my posts on Alexandre Dumas may be a weak and distant attempt of imitation. So now when I found it in a secondhand bookshop in Buenos Aires I bought it immediately, and read it again enjoying now not only the nostalgic aspect but also the often sharp and insightful philosophical reflections. (Savater is very well known in the Spanish-speaking world, but many of his other books seem overrated to me. He is at his best in this kind of short-scaled critical essay).

(*) If you are a reader from an Anglo-Saxon country chances are you have heard of and perhaps read all these authors except Salgari. His adventure tales are inmensly popular among Italian and Spanish speakers and almost unknown in the rest of the world. I promise to post something on him some other day.

7) Huw Price, Time's Arrow and Archimedes' Point. An excellent example of well-done philosophy of physics, discussing the fascinating problem of time asymmetry. I will post separetly on this one shortly, after rereading it and digesting its arguments and conclusions, because there is much in it of interest to readers of this blog.

Tuesday, July 04, 2006

How come I can't get a Mary Jane, then?

Your results:
You are Spider-Man

The Flash
Iron Man
Wonder Woman
Green Lantern
You are intelligent, witty,
a bit geeky and have great
power and responsibility.

Click here to take the Superhero Personality Quiz