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Comment author: Mitchell_Porter 25 May 2017 09:29:48AM 4 points [-]

Suppose there's some idea, X, which you think might help to solve a problem, Y. And there's also a dumb version of X, X', which you know doesn't work, but which still has enthusiasts.

And then one day there's a headline: CAN IDEA X SOLVE PROBLEM Y? Only you find out that it's actually X', the dumb version of X, that is being presented to the world as X... and nothing is done to convey the difference between X' and the version of X that actually warrants attention.

That is, more or less, the situation I find myself in, with respect to this article. I wish there were some snappier way to convey the situation, without talking about X and X' and so on, but I haven't found a way to do it.

Problem Y is: explain why quantum mechanics works, without saying that things don't have properties until they are measured, and so on.

Idea X is, these days, usually called Bohmian mechanics. To the Schrodinger equation, which describes the time evolution of the wavefunction of quantum mechanics, it adds a classical equation of motion for the particles, fields, etc. The particles, fields, etc., evolve on a trajectory in state space which follows the probability current in state space, as defined by the Schrodinger equation.

The original version of this idea is due to de Broglie, who proposed that particles are guided by waves. This was called pilot-wave theory, because the wave "pilots" the particle.

Pilot-wave theory was proposed in the very early days of quantum theory, before the significance of entanglement was properly appreciated. The significance of entanglement is that you don't have one wavefunction per particle, you just have one big wavefunction which provides probabilities for joint configurations of particles.

A pilot-wave theory for many particles, in the form that de Broglie originally proposed - one wave per particle - contains no entanglement, and can't reproduce the multi-particle predictions of quantum mechanics, as Bell's theorem and many other theorems show. Bohmian mechanics can reproduce those predictions, because in Bohmian mechanics, the wavefunction that does the piloting is the single, entangled, multi-particle wave used in actual quantum mechanics.

All this is utterly basic knowledge for the people who work on Bohmian mechanics today. But meanwhile, apparently a group of people who work on fluid dynamics, have rediscovered de Broglie's original idea - "wave guiding a particle" - and are now promoting it as a possible explanation of quantum mechanics. They don't seem to care about the theorems proving that you can't get Bell-type correlations without using entangled waves.

So basically, this article describes the second-rate researchers in this field - in this case, people who are doing the equivalent of trying to force the square peg into the round hole - as if they are the intellectual leaders who define it!

Comment author: Rubix 02 February 2013 01:17:50AM 25 points [-]

"In any man who dies, there dies with him his first snow and kiss and fight. Not people die, but worlds die in them."

-Yevgeny Yevtushenko

Comment author: Mitchell_Porter 02 April 2017 12:34:23PM 2 points [-]

Ironically, the man Yevtushenko is now dead too; but the world Yevtushenko, asteroid number 4234, lives on.

Comment author: Douglas_Knight 23 March 2017 09:02:15PM 1 point [-]

No, there is no evidence of such replication. This isn't really compatible with gays being detectable at age <5. Also, it's pretty clear that isn't what happens in sheep, which are highly analogous.

Common infections can have effects on a small population. For example, Barr-Epstein is implicated in at least some cases of narcolepsy, but 95% of the population tests positive for it.

Comment author: Mitchell_Porter 30 March 2017 10:10:09AM 1 point [-]

What about pederasty in ancient Greece, what about sex in all-male prisons... in both those cases, you have men who by current definitions are not gay, but rather bisexual. And in both cases you have recruitment into an existing sexual culture, whether through seduction or coercion.

Human sexuality can clearly assume an enormous variety of forms, and I don't have a unified theory of it. Obviously genes matter, starting with the basic facts of sex determination, and then in a more elusive way, having some effect on sexual dispositions in the mature organism.

And yes, natural selection will be at work. But, in this case it is heavily mediated by culture (which is itself a realm of replicator populations), and it is constrained by the evolvability of the human genome. I continue to think that the existence of nonreproductive sexuality is simply a side effect of our genomic and evolutionary "business model", of leaky sexual dimorphism combined with Turing-complete cognition.

Comment author: Douglas_Knight 21 March 2017 02:56:48PM 0 points [-]

Are there any ideas about how and when the gay germ is acquired?

If someone hasn't experienced sex yet, but they already think they are gay, is that because of the gay germ?

Gays generally say that they "always knew they were different" (and there is some evidence that this is not just confabulated memories), so it is probably acquired before age 5, possibly before birth. It is probably something common, like the flu. And there might be multiple infections that cause the same brain changes, as appears to be the case with narcolepsy.

If homosexuality has such a huge fitness penalty, why haven't we evolved immunity to the gay germ?

You could ask a similar question about any explanation of homosexuality. It is measured to be weakly heritable. So we know that there are genes that protect from it. Given the fitness penalty, why haven't those genes swept through the population? That wouldn't necessarily eliminate it, but they would eliminate the heritability.

There are only two possibilities: either the fitness penalty is not what it looks like (eg, the sexual antagonism hypothesis); or the environment has changed so that which genes protect has changed.

Germ theory gives a simple explanation for changing environment, The Red Queen Hypothesis: the germ is evolving, so the genes that protect against it are changing. This is the metric that Cochran and Ewald use: multiply the fitness cost by the heritability. The higher that number, the more likely the cause is infection.

Comment author: Mitchell_Porter 23 March 2017 07:31:20PM 1 point [-]

There actually is a known replicator that assists the reproduction of gay phenotypes, but it's a behavior: gay sex! For a recent exposition, see the video that cost "Milo" his job.

Comment author: Douglas_Knight 18 March 2017 06:03:29PM 0 points [-]

I thought Cochran was a science-jock who couldn't imagine being gay

Whereas you can imagine it so easily that you didn't bother to look at the real world, just as you can imagine Cochran so easily you didn't bother to look at him

how seriously I should take the argument that there has to be (in gwern's words) a "mechanism... to offset the huge fitness penalty"

90% of biologists don't believe in evolution, either, but progress comes from those who do.

Comment author: Mitchell_Porter 21 March 2017 10:59:22AM 1 point [-]

I believe in evolution, I just don't believe in the gay germ.

But regardless of belief... I have some questions which I think are fair questions.

Are there any ideas about how and when the gay germ is acquired?

Are there any ideas about its mechanism of action?

If homosexuality has such a huge fitness penalty, why haven't we evolved immunity to the gay germ?

If someone hasn't experienced sex yet, but they already think they are gay, is that because of the gay germ?

Comment author: Mitchell_Porter 19 March 2017 12:12:14AM *  0 points [-]

Give it all to Fabian Tassano.

Comment author: Douglas_Knight 14 March 2017 07:48:25PM 1 point [-]

The gay germ theory is pretty silly

You only posit that because your paranoid ignorance of biology.

Cochran has a paranoid intuition that something else is happening, so he posits his gay germ

Bullshit. Cochran wrote down his exact thought process. He thinks that everything is due to germs. Moreover, he measures of the strength of the evidence. Schizophrenia and (male) homosexuality are at the top of the list

Comment author: Mitchell_Porter 18 March 2017 07:27:19AM 3 points [-]

OK, let's talk about proximate causes and ultimate causes. The proximate causes are whatever leads to the formation of a particular human individual's sexuality. The ultimate causes are whatever it is that brought about the existence of a population of organisms in which a given sexuality is even possible.

My focus has been on proximate causes. I look at the role of fantasy, choice, and culture in shaping what a person seeks and what they can obtain, and the powerful conditioning effect of emotional and sexual reward once obtained, and I see no need at all to posit an extra category of cause, in order to explain the existence of homosexuality. It's just how some people end up satisfying their emotional and sexual drives.

What I had not grasped, is that the idea of the gay germ is being motivated by consideration of ultimate causes - all this talk of fitness penalties and failure to reproduce. I guess I thought Cochran was a science-jock who couldn't imagine being gay, and who therefore sought to explain it as resulting from an intruding perturbation of human nature.

I am frankly not sure how seriously I should take the argument that there has to be (in gwern's words) a "mechanism... to offset the huge fitness penalty". Humanity evolves through sexual selection, right? And there are lots of losers in every generation. Apparently that's part of our evolutionary "business model". Meanwhile I've argued that non-reproducing homosexuality is a human variation that arises quite easily, given our overall cognitive ensemble. So maybe natural selection has neither a clear incentive to eliminate it, nor a clear target to aim at anyway.

Comment author: gwern 12 March 2017 04:18:07PM *  3 points [-]

That theory is even worse than the inclusive fitness one because you offer no mechanism whatsoever to offset the huge fitness penalty.

Sexual imprinting is a highly successful evolved mechanism critical to reproductive fitness which does in fact succeed in the overwhelming majority of cases; in many ways, it is more important than trivial details like 'eating food' because at least an offspring which immediately starves to death doesn't drain parental resources and compete with siblings and the parents can try again! There should be a very good reason why such an important thing, found throughout the animal kingdom in far stupider & less sexually-dimorphic organisms, goes wrong in such a consistent way when other complex behaviors work at a higher rate and fail much more bluntly & chaotically. 'Random imprinting' is too weak a mechanism to thwart such a critical device, and doesn't explain why the errors do not rapidly disappear with general or sex-linked adaptations. (Even as a 5% liability-threshold binary trait, a reproductive fitness penalty of 50%, to be generous to a trait which involves active aversion to procreative sex, would imply it should be far lower now than when it first arose*.)

Further, such a random nonshared environment theory doesn't explain why dizygotic and monozygotic same-sex twins differ in concordance. (They don't differ in language, so your example is evidence against your imprinting theory.)

* https://www.researchgate.net/profile/J_Bailey2/publication/21311211_A_genetic_study_of_male_sexual_orientation/links/02e7e53c1a72a8a596000000.pdf gives a low end heritability estimate of 0.31; population prevalence among males is usually estimated ~5% giving a liability threshold of ~-1.64; homosexuality is amply documented for the past 2500 years or so, at least back to the ancient Greeks, which at a generation time of ~25 years, means 100 generations. So assuming a fitness penalty of 'just' half and that selection started only 100 generations ago (rather than much further back), we would expect the rate of homosexuality to be less than 1/5th what it is.

 threshold_select <- function(fraction_0, heritability, selection_intensity) {
library(VGAM) ## for 'probit'
fraction_probit_0 = probit(fraction_0)
## threshold for not manifesting trait:
s_0 = dnorm(fraction_probit_0) / fraction_0
## new rate after one selection:
fraction_1 = pnorm(fraction_probit_0 + heritability * s_0 * selection_intensity)
return(fraction_1)
}
threshold_select(0.95, 0.31, 0.5)
# [1] 0.9517116257
fractions <- 0.95
for (i in 2:100) { fractions[i] <- threshold_select(fractions[(i-1)], 0.31, 0.5); }
round(fractions, digits=3)
# [1] 0.950 0.952 0.953 0.955 0.956 0.958 0.959 0.960 0.961 0.963
# [11] 0.964 0.965 0.966 0.966 0.967 0.968 0.969 0.970 0.971 0.971
# [21] 0.972 0.973 0.973 0.974 0.974 0.975 0.975 0.976 0.977 0.977
# [31] 0.977 0.978 0.978 0.979 0.979 0.980 0.980 0.980 0.981 0.981
# [41] 0.981 0.982 0.982 0.982 0.983 0.983 0.983 0.983 0.984 0.984
# [51] 0.984 0.984 0.985 0.985 0.985 0.985 0.986 0.986 0.986 0.986
# [61] 0.986 0.987 0.987 0.987 0.987 0.987 0.987 0.988 0.988 0.988
# [71] 0.988 0.988 0.988 0.989 0.989 0.989 0.989 0.989 0.989 0.989
# [81] 0.989 0.990 0.990 0.990 0.990 0.990 0.990 0.990 0.990 0.990
# [91] 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.99
Comment author: Mitchell_Porter 13 March 2017 06:48:33AM 1 point [-]

My guess is that it's somehow a spandrel of intelligence.

Comment author: gwern 12 March 2017 02:05:07AM *  4 points [-]

Aside from the inclusive fitness claim, Cochran's gay germ hypothesis is also consistent with the continued existence of homosexuality: the pathogen co-evolves and so while the genes do get selected against, which genes keeps changing. Unfortunately, his theory still remains something of a 'germ of the gaps' theory - no one's come up with a remotely plausible theory or found decent evidence that homosexuality spikes the fertility of relatives so much as to compensate for the sterility of homosexuals (remember, inclusive fitness decreases fast: if a homosexual has 1.05 rather than 2.1 children, then their siblings have to have 2.1 additional children, their cousins 4.2 additional children, and so on), so a theory which merely isn't contradicted by any evidence looks pretty good by comparison.

One thing I thought of which would be direct evidence for the infection theory: polygenic scores for homosexuality. It's somewhat heritable, so given a large sample size like UK Biobank, it should be possible to explain a few % of variance and construct a PGS based on a fairly narrow age cohort like 1 or 2 decades. Then the PGS can be applied longitudinally outside the sample. If it's pathogenic co-evolution and the relevant genes keep changing, then the homosexuality PGS should show highest predictive validity in the original age bracket, but then decrease steadily as one moves away from the age bracket into the past or toward the present, showing a clear inverted V shape. While polygenic scores can increase or decrease steadily or show sudden shocks for various reasons just like heritabilities can increase/decrease over time (eg education PGS decrease due to dysgenics, height PGS increase and so on), they don't typically show a distinct V shape, so finding one for homosexuality would be very striking.

Comment author: Mitchell_Porter 12 March 2017 03:00:56AM 3 points [-]

My theory and meta-theory: The gay germ theory is pretty silly. But the big myth to which it is a reaction, is the idea that people are simply "born that way". Cochran has a paranoid intuition that something else is happening, so he posits his gay germ. But what's really happening is sexual imprinting. A person's sexuality is greatly shaped by the first conditions under which they experience arousal, orgasm, and emotional bonding. Sexualities are "transmitted" in a way a little like languages. There's no "German germ" which makes people think and speak auf deutsch, instead there's some sort of deep learning based on early experience of a German-speaking environment. The acquisition of sexuality might be more like conditioning than learning, but it's still an acquired trait.

Comment author: [deleted] 04 May 2016 04:57:30PM 1 point [-]

I wonder at the timing of this article and upcoming workshops.

I'm not deep in the AI community... did something happen recently to spark greater interest and preparation for AI? Any big news story I somehow missed?

Maybe the topic's been on the backburner at the White House and they're only just getting it started now; regardless, it sounds promising.

Comment author: Mitchell_Porter 06 May 2016 09:56:06AM 3 points [-]

The big new problem in presidential decision theory is Coherent Extrapolated Trump.

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