Recent Reading

Some notes on books I have read in the past two or three months

-Philip Roth, The Plot Against America. First book I read by him, this an alternative history in which famous aviator and anti-Semite Charles Linbergh was elected president of the United states instead of Roosvelt in 1940. Told from the point of view of an American Jewish child growing up in a climate of increasing fear and persecution, the story is remarkably well-written and the political setting chillingly believable. The largest problem is a deus-ex-machina ending which solves rather too simply all the problems created in the story

-Denis Guedj, The Parrot's Theorem. A popularization history of mathematics thinly disguised as a thriller, in the line of what Jostein Gaarder did for philosophy in Sophie's World, but less successful. The mystery plot is too contrived and implausible too keep the attention of the reader, and the mathematics is very dumbed down (there are almost no equations). If you are a layman wishing to learn some mathematics, stick to nonfiction, like Simon Singh. Fiction can be excellent if it embodies mathematical ideas, as in some Borges stories for example, but it is a poor medium for explaining mathematics in a pedagogical way.

-Laurie M. Brown (ed.), Renormalization: from Lorentz to Landau (and beyond). Collection of essays on the historical progression of ideas on renormalization in quantum field theory, including an excellent essay by Tian Yu Cao on the "new philosophy" of effective field theory. Recommended.

-Kate Fox, Watching the English. An amusing anthropological study on the cultural customs of that strange tribe, the English. With all the rules to understand pub discussions, ironic humour, awkward introductions, obsessive queuing, subtle linguistic class distinctions, and much more. A must read if you live here or are planning a visit.

-Ursula K. Le Guin, The Dispossessed. First I read by her, a story in classic SF style about two contrasting alien societies, one anarchistic and one capitalistic, with the protagonist being raised in the former and then moving to the latter. Some insightful social philosophy compensates for a somewhat slow plot. Overall I liked it and I'm likely to try more by her.

-Terry Pratchett, Darwin's Watch. Once more, this is the first book I've read by him. (Seriously!) Our universe, Roundworld, is kept in a one-foot long glass globe in the meta-universe of Discworld, where the wizards of the Unseen University have to find a way to interfere with human history to ensure that a certain Charles Darwin writes the "right" book instead of the one he has written in the present timeline, a vindication of Paley's design argument by the title of The Theology of Species. (In this alternative timeline, the true theory of evolution was not discovered until a hundred years later by one "Rev. Richard Dawkins" -Rev. because only theologians could be biologists after the success of Darwin's book. I loved that detail!) The book mixes comic fantasy with scientific popularization chapters written by Ian Stewart and Jack Cohen. Pratchett's style of humour reminds me of Douglas Adams', a particular kind of British humour which is engaging at first and becomes tiring after longer exposure. I have not become tired of Pratchett's yet, though, so I am likely to read some more by him. I know there is a huge literature on Discworld: any particular recommendations?

-Karen Armstrong, The Great Transformation. A serious book on history of religion, to compensate for the one that follows on this list. Armstrong traces the development of religious and philosophical views in China, India, Israel and Greece in the so-called Axial Age, ranging from 900 to 200 BC, the time of Buddha, Confucius, Laozi, Isaiah, Jeremiah, Pythagoras, Socrates, and many other key figures that created ways of thinking about the universe, mankind and our ethical duties that are still living with us. Fascinating reading about a period that has interested me since I read Gore Vidal's novelistic account in Creation. The only thing that put me a bit off was Armstrong patronizingly saying that the Greeks only entered halfways in the deep spirit of the Axial Age; to my mind inventing scientific rationalism, tragedy and democracy is a much more impressive achievement than inventing ethical philosophies which, no matter how sublime and insightful, few people ever followed to a full extent. But we are all entitled to our biases, aren't we?

-Richard Dawkins, The God Delusion. Yes, I after all that fuss and reading reviews and reviews of reviews and commenting on them, I finally read the book. It was less substantial than it seemed by skimming through it at the bookshop, and more or less what the reviews would have lead me to expect: a sort of Atheism 101 textbook. The level is the same as your average Pharyngula comment thread: some insightful, learned or witty commentary mixed together with a lot of trite arguments, simplifications, and even childish jabs. I love the Flying Spaghetti Monster, for example, but we must admit that to use it in a (anti)theological argument is equivalent to losing all pretensions of academic seriousness. That is not to say that I decry the writing of this book: there are probably a lot of people who have been indoctrinated with dogmatic faiths for whom reading it could have a liberating effect, and the outreach of this kind of book is far larger than that which a scholarly refutation of the latest argument by Plantinga could have. I would much prefer to read the latter, but then, I became an atheist long ago already, and partly by reading, reflecting on and re-elaborating by myself arguments that were at first no better than the ones Dawkins champions. If Dawkins was only intending to write a simplified "atheistic primer for the masses" I would be less annoyed than I am when I see that he thinks his arguments can challenge the views of serious theologians. The main point at which this happens is at his famous "Ultimate 747 Argument"; I will probably dedicate a post soon to analyze it and show, contra Dawkins, that is doesn't prove that "there is almost certainly no God" -but that an argument related to it can be used to argue that there is "probably" no God, though this "probably" is much more qualified and uncertain than Dawkins'.

Obligatory Harry Potter predictions post

(Warning: this post contains huge spoilers for all the already published Harry Potter books. And perhaps for the seventh as well, though I’d rather wish not, and be surprised…)

Well, it’s now less than two months’ time to the publication of Harry Potter and the Deathly Hallows, and everybody and their mother are posting their theories and predictions. And though I have arrived lately to the fun (I didn’t think much of the early books when I read them for the first time, and only became a true fan after the sixth), I don’t want to miss the chance of embarrassing myself with confident predictions that will be shattered to pieces when we read that “the Giant Squid is actually the world's largest Animagus, which rises from the lake at the eleventh hour, transforms into Godric Gryffindor and...” (as Rowling has whimsically said)

So, let’s go. There are two main points of controversy among fans: whether Harry is or not a Horcrux, and whether Snape is Good or Evil.

On the first, I am quite sure that he is. Dumbledore’s theory that the snake Nagini is the sixth Horcrux is an obvious red herring; it struck me as dodgy even the first time I read it. Harry being a Horcrux explains too many things:

1) The strange and unnatural scar is likely a mark left by the Horcrux-creating spell, and probably the precise locus where the soul fragment is enclosed.

2) The telepathic connection with Voldemort, which is natural and expected if they share parts of the same soul.

3) The transmission of Parselmouth power to Harry.

4) The fact that Harry could destroy so easily Riddle’s diary in CoS, while the much wiser and abler Dumbledore lost a hand trying to destroy the ring Horcrux. It is likely that the curses with which Voldemort protected the Horcruxes would not act against the same soul they harboured.

5) The fact that Voldemort couldn’t sustain possession of Harry at the end of OoTP. It is likely that something goes screwy if you try to put together again the two disjointed soul fragments.

6) The fact that in HBP Voldemort orders the Death Eaters not to kill Harry, as we know courtesy of Snape.

The way I see things, Voldemort had planned to use the murder of baby Harry as means to create his last Horcrux, as Dumbledore surmised. The spell went wrong thanks to Lily’s sacrifice and Voldemort’s original body was killed (what happened to it, by the way? It was not found. Did Pettigrew dispose of it? It’s difficult to believe he would have cared to.) but the Horcrux was created anyway. Voldemort didn’t realise this at first, and that’s why he implied to the Death Eaters in the graveyard scene in GoF that he had not archived immortality yet; he thought he needed one more Horcrux to have the magical number of seven soul-parts. He still hadn’t discovered the truth by the end of OoTP, when he tried to kill Harry with an Avada Kedavra. He probably figured it out after the failed possession attempt, and that’s why in HBP he switches his attention to getting Dumbledore killed and gives explicit orders that the Death Eaters not kill Harry.

So, will Harry eventually have to sacrifice himself to destroy Voldemort? I’m afraid it is very likely. But Rowling has also said in an interview (upon asked about her religious beliefs) that she is a Christian but that “if she talked too freely about that any intelligent reader, whether 10 or 60, will be able to guess what's coming in the books”. Putting this clue together with the previous line of reasoning I conclude that we are heading for a resurrection scene. Of course, it may be that she was thinking only that Harry sacrifices himself to save the world, but I don’t really think so. It would be too gloomy an ending, and also contradict the Prophecy. It is more likely that he will intend to sacrifice himself, but somehow only the fragment of Voldemort’s soul is killed while Harry miraculously survives, perhaps after passing by dead for some time. I also think (hope?) it is unlikely that Ron, Hermione or Ginny will take a bullet, although the future looks very dark indeed for Hagrid.

Now, about Snape. The first thing here is that the “Evil Snape” scenario that Harry and his friends accept at the end of HBP does not hold water for a second. There are too many indications that Dumbledore had arranged with Snape that he should kill him if the situation came to a crisis in which there was no other way out. Let’s go through the main arguments:

a) Hagrid overheard a discussion in which Dumbledore ordered Snape to do something Snape seemed to be reluctant to do. This did not receive any explanation by the end of the book. The most reasonable theory is that the order was to kill Dumbledore if it came to be necessary to preserve Snape’s status as spy, and indeed his life, since he had made an Unbreakable Vow.

b) Dumbledore obviously knew everything about the Unbreakable Vow and Draco’s mission; this is made clear both by his nonchalant reaction to Harry’s information about the conversation he overhead between Snape and Draco, and by his conversation with Draco himself in the tower. He knew it from Snape (from who else?) Snape would not have told him about all this if he was really Voldemort’s servant.

c) Dumbledore’s plea “Severus… please…” only makes sense as a plea to kill him. Dumbledore would not have begged for his life, and the alternative theory that he was begging to Snape not to kill him, for the sake of Snape himself, is still unconvincing. If Dumbeldore had believed up to that moment Snape that Snape was on his side, why would he plea not to kill him? He would have expected him to tackle the Death Eaters instead.

d) Snape’s extreme reaction against Harry calling him “coward”, which makes sense if he has just done something very brave.

e) Snape only taunting Harry but not hurting him with any serious curse when he has him at his mercy.

f) We still haven’t discovered the reason why Dumbledore trusted Snape’s loyalty (it is not, as Harry assumed, just remorse on being cause of the death of James and Lily. Dumbledore never said that nor even implied it, if you read carefully.) We must be explained that in Book 7, and from a storytelling standpoint it would be all wrong if we were explained this point that was a key secret for the whole series in a context of “ha, that fool Dumbledore believed this!”

These arguments and other ones have convinced the majority of fans that Snape is “good”, and I have seen many an essay that portraits him as a loyal agent of Dumbledore, courageous and selflessly dedicated to the task of vanquishing Voldemort. I have difficulty picturing him in this heroic role. As he is portrayed in the books, he is petty, jealous, unfair, vindictive, and often sadistic, not only with Harry but with all his students except a few Slytherins. This ambiguity is, of course, the reason that makes him so fascinating.

My view of Snape is that he is an essentially self-centred person who does not live by ideals of good and evil, but simply tries to survive. He may care for a few other people (his concern for Draco seems genuine and not exclusively motivated by his Vow) but he does not care for saving the world from evil or anything like that. I would speculate his strongest desire is to be free from teaching stupid kids and be able to study the Dark Arts at leisure. Not for desire of power, but just because they fascinate him. Snape is not a Dark Arts freak; he is a Dark Arts geek. After signing up with the Death Eaters and seeing what it was all about he changed his mind, because no matter how much he hated and craved revenge on a few people like James Potter and Sirius Black, he did not have a taste for having absolute power over everyone or making everyone suffer. He just wanted everyone to leave him alone. And he was intelligent enough to realise that under Voldemort’s thumb he would be even less free that under Dumbledore’s.

So he sought Dumbledore’s protection to try to get out safely of the Death Eaters gang, and he found he was trapped. Because he was in an ideal position to spy for Dumbledore, and could not refuse his insistence to do so; besides, he could not openly leave the DEs or they would have killed him. So he was forced since then to live as a double agent, a role he didn’t play out of heroism but out of necessity and for which, as an Occulmens, he was eminently suited. In HBP he was under terrible pressure from all sides (Voldemort, Dumbledore and the Vow he made to Narcissa) and finally had no option but to kill Dumbledore, which was where all three sources of pressure pressed towards.

Dumbledore didn’t care to continue living once he had put Harry on the track to destroy the Horcruxes, and thought Snape’s life was much more important than his to provide “inside help” to Harry in his mission. But Snape did not want to be put in this situation. He lost his protector, and is forced to fight alone now playing his role with Voldemort and having to hide from the rest of the world who sees him as a murderer. Moreover, he has (at least, on Dumbledore’s orders) to assist Harry and provide him with the help he requires to play his role as Chosen One and destroy Voldemort. And Snape sincerely and utterly loathes and despises Harry. He has been forced by circumstances and Dumbledore’s plans into a position he never wanted to be in, to play a role which he hates but sees no other option than performing. He is not a “born hero” as Harry is: he has been thrust into a hero’s place against his will. That’s why he could feel sincere hatred and revulsion when he cast the Avada Kedavra at Dumbledore, and that’s why he got into a frenzy at being called coward. He is now unstable and unpredictable. He may still overcome himself and help Harry as Dumbledore wanted, but he may also snap and try to play his own game against both Voldemort and Harry, or even switch sides to Voldemort at the last moment.

As you see, even after having reconstructed his whole story and (I believe!) successfully puzzled out the riddle of his character I am still unable to predict what role will he play on the final denouement and what his end will be. I used to think he would die a noble and “redeeming” death sacrificing himself for Harry, but I realised later that this role or a very similar one is already reserved for Peter Pettigrew. At the moment I am inclined to think he will grudgingly do the right thing, stand on Harry’s side, and that after destroying Voldemort both will be forced at the end to revise their view of each other, admit their respective virtues, and thus take a large step in growing up. (For all his cleverness, Snape is very immature in many ways –witness his petty taunts against Sirius in OoTP, and his behaviour towards Harry in the whole series just on behalf of his father.) This –Harry coming to terms with adulthood in forgiving and accepting a matured Snape- could make an excellent ending if it is played well. But perhaps I am being too optimistic -this would be an ending too rosy for the darkness that has encompassed the series lately, wouldn't it?

Well, I have many more ideas, but you really must be tired of hearing them. What are your own predictions?

Link and Notes

I've been a Bad and Lazy blogger lately, and I am likely to remain so for some time. The reason is that I've started to write a new paper, and when I pass most of my working hours writing I don't feel like writing for fun in my free time. Writing for fun works better as a rest after a day spent calculating. (What, you say I should also consider the possibility of getting a life? What is that?)

So here a few interesting links I have collected lately, all of them on the kind of subjects you might have seen at some time discussed in this blog:

-The FQXI Community webpage for fundamental questions in physics looks very cool. I recommend especially Matt Leifer's post "Is the world made of wave-vectors?", an extremely clear and concise summary of the pros and cons of "ontological" and "epistemic" interpretations of quantum mechanics.

-I don't intend to become any sort of chronicler of the new papers appearing in the quantum gravity community (the guys at Physics Forums take care of that) but given that this new spin foam model appeared today and seems possibly important, I thought I might just as well link to it. Also there is this recent one by Ashtekar, based on his "LQG FAQ" talk at MG11, which I blogged about last year.

-At the n-Category Cafe, a fun quiz to give your probability estimates for whether a number of quasi(?)-mythological(?) figures (ranging from Gilgamesh to Robin Hood) actually existed. The discussions in the comments involve both what it means for X "to have existed" (descriptive vs. causal theories of proper names) and what it means to assign a probability to it (Bayesianism vs. others).

-Via Thoughts, Arguments and Rants I found this interesting paper, which describes a recent mathematical result which may be of unexpected relevance for the centuries-old philosophical problem of induction. Would old David Hume ever have guessed that there is a rule which, given any function on the real numbers and its values up to (but not including) a certain T, can predict its value at T correctly, for almost all values of T? I'm sure not! What I'm not sure is how relevant this is for the traditional problem -especially given that the theorem only assures the existence of a rule, without explicitly providing one.

-Talking about Hume, Brandon has been putting up some notes on reading and interpreting his Dialogues Concerning Natural Religion. This is one of my favourite philosophy books, so I am following this series of posts with great interest. The posts are: Part one and two, Part two and three, Part four and five.

Quantum Mechanics in words of one syllable

Some think Quantum Mechanics is impossible to explain in simple terms. To refute this idea I have composed this piece, which is inspired both by the “Theory of Relativity in words of four letters or less” and by “Philosophy in words of one syllable”. I have not used any kind of dictionary or thesaurus.


In this piece we will talk of small things and how they are. How small, you ask? Well, close to the scale of Planck’s h. This will mean the bits of stuff the world is made of: the bit of charge, the bit of light, and so on. These small bits are quite weird, not at all like the large stuff we are used to.

If you have a set of those bits, at each time it will be in a state. We write the state as a ket, as Paul taught us. The ket for state A looks like this: IA>. The ket has in it all one can know of the small bits we talk of. The state will change in time, of course. To say how much it will change per sec (its rate of change) we have a rule Er told us: i times the rate of change of the ket is H times the ket. H is a key thing; it keeps track of how much stuff is there is, the mass of each bit of stuff, which is the force that acts on each bit, and so on.

So we know how states change, fine. How do we get from this to a claim on what we will see in the lab? Here is where things are not like we are used to. In the large world we are used to, when we know the state of a thing we know that if we look at the thing we will see it in that state. But here, if we know the state we can’t tell in which state will we see it. We will have a chance to see it in a new state. If it was in IA>, it may be that we see IB> when we look. We can’t tell for sure. But we can tell what chance we have to see each state.

For that we use a rule that a guy called Max Born gave us. To get the chance to see state B when you look at some stuff that is in state A at that time, do some math called "ket A dot ket B", or IA> . IB>. What comes out of this math has to do with the chance to see B if the state is A. But it is not quite that, ‘cause the chance must be real and what we have now turns out to have i in it. Darned math! But just take the square of the real part and add to it the square of the part with i (that is, take the norm of what you have) and you will get the chance to see B if the state is A.

There are lots of things one can want to look at when one looks at stuff in the lab: Mass, charge, where bits are, how fast they move, and so on. For each of these things there are some states called “self states” of the thing. When the state is a self state of a thing, we can tell what we will see if we look at that thing. But in most states we can’t. As a case, if we add two self states IA> and IB> of a thing the new state IA> + IB> will not be a self state for that same thing. If this is the state, when we look at that thing we may see A or B, each with a chance of one half. Once we have looked, the state will be A or B; but not till we look.

This leads to the well known case of Er’s cat. If the state of some bits of stuff is IA> + IB>, and we put those bits in a box with a cat, and make things such that state A will in due time kill the cat, while state B lets it live, then the cat will not live nor die till we look in the box! Weird, huh?

I know you must want to say: “No way! For sure, the state was A or was B all the time, we just did not know which till we looked!” No such luck. If the state is IA> + IB>, then it may be that the A part and the B part “mix” and we can tell that the state was not “A or B” with a look at some things in which you see that mix. It is hard to do for a large thing, like a cat, ‘cause you would have to keep track of each bit of stuff; but it has been done for small things, and there is no clear line that breaks small from large.

Old Al did not like all this stuff. He was sure God did not play dice with the world. He and two pals came up with a thought to show all this must be wrong. Take two bits of stuff, say two light bits. Let the state be one in which both bits must have a thing not the same; say, one of them has “spin up” and one “spin down”, but the state makes not clear which has which spin. (Spin is like a turn ‘round that the bit may have; this turn may point up or down for each bit.) Let the two bits move a lot one each on its way, so they come to be far. Now look at the spin of the first bit. If you see it “up”, the spin of this bit has changed from an “up plus down” state to “up”, and the spin of bit two has changed at the same time from state “down plus up” to “down”. But how can the state of bit two change when we look at bit one, which is far from bit two? It makes no sense.

But it does. A smart guy called John Bell came up with a slick way to test this stuff, and it turned out that Old Al had been wrong for once. One is forced to grant that bits of stuff can “know” what goes on far, far from them, or else that in a sense things are not “out there” till we look at them! More and more weird, I say. It may be that some day we will make sense out of this. By now, guys are still not of one mind on what one should say. But, at the same time, with all this we can work out, know and grok lots of stuff. So it must be true. So when one starts to ask a lot, like “what does it mean”, some guys say: “Shut up and work!”

Coming next: Quantum Field Theory in words of one syllable. Quantum Gravity is much easier; one just needs to write: “What?”