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Our future, our universe, and other weighty topics

Thursday, November 20, 2014

Homosexuality Hard to Explain Using Darwinian Orthodoxy

Under the thinking encouraged by many a modern materialist, almost everything about us can be explained by evolution and our genes. But there are difficulties in such thinking, one of which is properly accounting for the widespread existence of homosexuality.

Darwinism is centered around the idea that evolution slowly increases the prevalence of traits which tend to increase an organism's likelihood to survive until reproduction (and also the likelihood of the organism's reproduction). So suppose there were two genes in different organisms of a species, one which caused very strong sexual interest, and another which caused complete lack of sexual interest. According to conventional evolutionary theory, the first gene would cause more reproduction, which would cause the gene to become more and more common (all other things being equal), as the gene was inherited more and more often; but the second gene would cause less reproduction, which would cause the gene to become less and less common, because the gene would be inherited much less frequently.

How, then, can we account for homosexuality using such principles? Surveys indicate that between about 2% and 6% of the population are gay or bisexual. Given that very many gay people would never answer “Yes” when asked if they are gay, the actual percentage may be even higher.

Today homosexuality is generally believed to be an inherent tendency, not a choice; so under Darwinian conventions we have little choice but to assume that homosexuality has a strong genetic component. It has been estimated that homosexuals reproduce at only 20 percent of the rate that heterosexuals reproduce. It would seem that a straightforward calculation using Darwinian conventions lead us to the conclusion that homosexuality should have died out long ago. Whatever genetic basis might be behind homosexuality should have become less and less common, because of the vastly lower reproduction rate of homosexuals. It would seem, therefore, that homosexuality shouldn't exist, at least not in its current prevalence of perhaps 5% of the population.

Biologist J.B.S. Haldane imagined a case in which 99.9 percent of the population had one gene, and only .1 percent of the population had a second gene. If there was some reason why the second gene was 1% more likely to be inherited, then within 4000 generations, things would completely switch around so that 99.9 percent of the people would end up with the second gene, and only .1 percent would end up with the first gene. The example illustrates how strongly evolution tends to get rid of genes that are less likely to be passed on to descendants.

So how can we account for homosexuality under conventional Darwinian assumptions? Some theories have been suggested, but they haven't been very convincing. In this article evolutionary biologist David P. Barash discusses some possibilities for explaining this paradox, but he just doesn't seem to be able to get to first base.

Barash first mentions “kin selection” as a possibility, saying of homosexuals “perhaps they are able to help their relatives rear offspring, to the ultimate evolutionary benefit of any homosexuality-promoting genes present in those children.” That's very speculative, and Barash gives no evidence to support it, except mentioning some tiny Samoan gay group which he claims “lavish attention upon their nieces and nephews.”

Then Barash mentions a “social prestige” theory, claiming that gay men became priests or shamans, and that “perhaps the additional social prestige conveyed to their heterosexual relatives might give a reproductive boost to those relatives, and thereby to any shared genes carrying a predisposition toward homosexuality.” But Barash admits that this idea is “lacking in empirical support,” which means there is no evidence for it.

Another theory for the survival of homosexuality is that it had something to do with what is called group selection. As Barash puts it, “Although the great majority of biologists maintain that natural selection occurs at the level of individuals and their genes rather than groups, it is at least possible that human beings are an exception; that groups containing homosexuals might have done better than groups composed entirely of straights.” Judging from that wording, it doesn't sound like that theory is on solid ground, since it contradicts an assumption made by the “great majority” of biologists.

Barash also mentions a “balanced polymorphism” explanation, saying “the possibility cannot be excluded.” Again, not a solid speculation, since no evidence is provided. He also mentions the possibility of “sexually antagonistic selection,” but says there is “no evidence for this idea.”

So while Barash mentions quite a few possibilities, he gives the reader no confidence at all that evolutionary biologists have any good explanation for why homosexuality has not died out because of evolutionary factors. Barash has nothing but strained speculations, and the only evidence he claims to have is a thin and dubious claim involving some tiny group in the distant islands of Samoa – a country with a total population of only about 200,000.

It would therefore seem that the large-scale existence of homosexuality is a significant problem for Darwinian orthodoxy. In fact, as I explained in this essay, Darwinian orthodoxy has quite a few difficulties accounting for numerous aspects of humanity, such as our abilities for math, language, philosophy, introspection, and tendencies such as spirituality, aesthetic appreciation, and altruism, most of which don't do much good from a “survival of genes” evolutionary standpoint. It would seem that while Darwinian concepts are a valuable contribution that explain a great deal, Darwinism may be seriously oversold as some kind of “this explains everything” theory to account for human nature.

These are hard to explain using only Darwinism

Could any unorthodox thinking lead us to other possibilities that might account for homosexuality?

I know of one unorthodox hypothesis about the cause of homosexuality. The hypothesis goes like this: (1) some people alive on Earth have had previous earthly lives; (2) a male homosexual is typically someone who was previously reincarnated as a female; (3) that person is attracted to males because of a residual attraction to males carried over from a previous life as a female. The only evidence for this hypothesis is the evidence for reincarnation, which may be much stronger than many people think, due to the research of Ian Stevenson at the University of Virginia.

Another unorthodox hypothesis is the hypothesis that a large part of the blueprint or schema for a human being is stored outside of a person's DNA. I explained this idea in my previous post entitled “Half of the Blueprint for You May Be Stored Outside Your Cells,” in which I pointed out the curious fact that the species of plant known as rice is believed to have 38,000 genes, but humans (almost infinitely more complicated) are believed to have only 23,000 genes. In that post I summarized this idea as follows:

Genes are a very important determinant of human nature. But as they are merely recipes for making proteins, we cannot at all explain all the exquisite features of human nature by assuming that the secrets of human nature are all stored in merely 23,000 genes. There may well be some completely undiscovered information storehouse that also is crucial in determining human nature – an unknown noncellular “dark genome.” When a human body and a full human mind comes into existence, it may require information from cellular genes and this mysterious noncellular“dark genome.”

If there is some kind of “dark genome” that might help to explain human nature, homosexuality could be an aspect of that, perhaps some permutation of human nature stored among various other permutations in that “dark genome” (here “dark” simply means currently undiscovered). This “dark genome” or “second genome” might be unrelated to reproduction rates, so within such an information storehouse the continued existence of traits related to homosexuality might be plausible enough.

Another unorthodox idea, which no doubt will infuriate some fundamentalists, is that homosexuality has been deliberately included as part of the human mixture by a higher power, who wants homosexuality to exist so that it can one day be a significant brake on out-of-control overpopulation.

These ideas are admittedly speculative – but no more speculative than the totally speculative musings of Professor Barash, who seemed “lost at sea” when trying to give an orthodox Darwinian explanation for why homosexuality still is widespread.

Postscript: According to the book Dataclysm: Who We Are by Christian Rudder, a Google researcher has reported that 5 percent of porn searches are for gay porn, and that such a percentage is consistent from state to state in the US. This data tends to back up both the idea that homosexuality is inherent, rather than something largely chosen (given the local drawbacks of "choosing to be gay" in some US states such as North Dakota and Mississippi); and it also suggests a relatively high gay population (5% rather than just 2%). Such data tends to accentuate the explanatory problem mentioned in this post.