[kikishortler]

Many of the religious ideas about masturbation were wrong, e.g. that it caused blindness. These ideas were created by priests who felt guilty about masturbating.

Many of the modern ideas about masturbation are also wrong, e.g. that it is 'healthy'. These are merely scientistic attempts to reverse the former shaming and guilt.

For me the question remains: is masturbation any better or worse than taking drugs?

[Waterluvian]

I will always bet on what comes natural to most to be healthy.

It's absurd to think we evolved "wrongly" and need to fight natural tendencies.

[burkaman]

Is your only life goal to survive long enough to reproduce? If you want more than that out of life, it's at least plausible that you might need to second guess some of your natural instincts.

[zkhalique]

Perhaps those who wanted more than that out of life had less genetic fitness than those who wanted exactly that out of life, so most people want that out of life.

On the other hand, I'm not sure how to explain the presence of homosexuality in a population when the theory of evolution predicts that any such trait (which leads to much lower genetic fitness) would have disappeared a long time ago. How does it stay at this level from generation to generation?

[sevenless]

The basic flaw in this is that there's no straightforward heritability for homosexuality, so regardless of the evolutionary pressures, it's not something that could be obviously 'selected against'.

Homosexual men throughout history did reproduce, though. In many ancient societies, norms were such that you had kids (if you survived long enough), and what you did with other men on the side was more or less your business. The Romans had a lot of gay sex, but didn't have a concept of a gay man, rather an effeminate man (who liked to bottom). So homosexuality is not really a puzzle that begs for a solution. The reality is, that the reasons we have sex do not have much to do with reproduction. Western society is still rather prudish about acknowledging this.

It's worth pointing out also, men generally pass their genes on a whole lot less than women do. Genetic evidence shows women were twice as likely as men to reproduce. So it's not like being heterosexual meant you'd have kids, being homosexual meant you wouldn't. I guess monogamy would reduce the disparity between men and women here.

http://www.eurekalert.org/pub_releases/2004-09/uoa-ges091604...

[bhaak]

I think I recall some articles about studies that showed that homosexual people (that don't reproduce themselves) are useful as caretakers for close relatives as they want to ensure the survival of similar genes.

Your question is similar to the question why old humans don't just die off when they can't reproduce anymore. This is most obvious with women when they enter menopause but also the quality of sperm declines with men with age.

They are either useful to some extent to reproduction or improving the survival rate of the offspring, or at least the evolutionary pressure is too small to eradicate these traits.

But as we have descended from group animals, I suspect the former.

[vidarh]

A gene survives and spreads if the gene helps increase the average fitness of the part of the population having the gene.

There is nothing about evolution that requires a gene to benefit any given individual. There are plenty of species where individuals are metaphorically "thrown under the bus" for the survival of genetically similar enough individuals to be worth it.

And for any given individual, a gene that confers high fitness on the population it exists in as a whole can still be disastrous in certain configurations.

An example of that would be the sickle-cell trait, which causes lots of deaths amongst those unlucky enough to get it from both parents, as it leaves them prone to sickle cell anaemia and related problems.

It survives in many regions such as West Africa because while receiving it from both parents cuts an average 20-40 years of your life expectancy in developed countries, "just" having the trait from one parent is a net positive because it makes it a lot less likely you will get malaria, which is a far bigger killer in countries with poor healthcare.

This is the convoluted way of saying that you can't look at the effect on individual survival - there can be convoluted mechanisms that makes a gene that makes your copies less likely to be propagated more fit on average.

[ta0967]

explain the presence of homosexuality in a population when the theory of evolution predicts that any such trait (which leads to much lower genetic fitness) would have disappeared a long time ago

one's homosexuality may improve fitness of one's family: if we're brothers and i'm homosexual, we won't be splitting resources between your and my children, and i'll be an extra "parent" looking after your kids. genetically speaking, that is still a (qualified) success for me.

also, genes don't give a damn about individual's reproduction, and local optima are rampant.

edit: what siblings have said.

[joeyo]

Re: homosexually, there are several possibilites. A plausible explanation is that it's linked with genes that confer fitness to siblings. As with most traits, however, it's likely to have both heritable as well as environmental antecedents.

[fulafel]

Reproduction and dying off is not our natural instinct, it's not the strategy chosen by our genes. Humans have evolved to form families, communities and rich cultural systems to serve our "selfish genes". To see the reproduction maximizing strategy in action, you can look at other forms of life.

[Retra]

Our natural instincts are not to die after we reproduce.

Besides: http://lesswrong.com/lw/l0/adaptationexecuters_not_fitnessma...

We execute the adaptations we already have, we do not optimize for evolutionary goals. We have no obligation to pay them any mind whatsoever.

[aninhumer]

>Our natural instincts are not to die after we reproduce.

Well of course not, since we might be reproduce more if we stay alive longer. And we do start to die around the time we start to lose fertility, which isn't an "instinct" to die, but clearly our bodies are not adapted to live longer.

[Retra]

You think we're not adapted to live longer because it takes us 60+ years to die after the only ~14 to become fertile? That seems like evidence of us being adapted to live longer. We are actually the longest-lived land mammal on the planet. So why on Earth would you conclude the opposite?

[oh_sigh]

Tell that to post menopausal women

[nikcheerla]

This.

[return0]

It's absurd to think we evolved "rightly" either. Also, what about our environment? We clearly didnt evolve with concrete and steel, asphalt and gasoline.

[Waterluvian]

Yup. Apologies if it sounded like I was suggesting that. I just wanted to communicate that there's no "wrong" way for things to evolve. Evolution just is.

[zem]

sugar is a good counterexample to that

[oh_sigh]

Is food any better or worse than taking drugs?

[kasparsklavins]

It could be argued that food is a form of drugs. It does affect our brains in a psychological manner.

[witty_username]

> Many of the modern ideas about masturbation are also wrong, e.g. that it is 'healthy'. These are merely scientistic attempts to reverse the former shaming and guilt.

Why are they wrong? Could you elaborate?

[dwaltrip]

Your post would have been less downvoted if you provided thoughtful rational for your analogy between "drugs" and masturbation. Also, HN generally doesn't have a favorable opinion of the the way drug prohibition currently exists in the U.S., so that adds another complication to the comparison.

[return0]

You could then widen the question "Is any non-procreational form of sex worse than taking drugs ?"

[collyw]

You don't do both at the same time?

[throwanem]

Well, at the very least, all the neurochemicals involved are endogenous. That's got to count for something. As to the rest, I figure that if God meant humans to masturbate, He'd have made our arms long enough so we could reach our genitals.

[Klinky]

Saying someone who masturbates is going to become a sex/porn addict is just as bad as preists saying it leads to blindness. Really your post sounds like someone confused by their own shame.