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Comment by throwanem | Hacker News Reader

There is no such thing as "evolutionary purpose." Evolution is a stochastic side effect of lossy self-replication. There's no one involved to do any intending.

Traits that don't impact fitness are selected neither for nor against. And there's no distinction you can draw between traits that arise by happenstance and those for any other reason, because there never is any other reason.

So why be surprised that such a (presumably) durable epiphenomenon of human neural complexity, having once arisen by happenstance, should persist? There is quite literally no reason for it not to.

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But every trait or behaviour that survives on evolutionary timescales does serve (or did serve, in the case of vestigial features) a purpose. I'm not sure what the exact mechanism is for one's life flashing before the eyes, but the researchers mentioned a very specific alignment of brain wave patterns that seems a bit too intricate to be purely random.

For a complex feature to pass through generations, it has to have some relative positive fitness associated with it. If it didn't provide some survival or fitness advantages, random genetic mutations would simply prevent the effect from being created. It is likely a very ancient survival mechanism based on these NDE existing through many different cultures and eras, and possibly not even specific to humans.

> specific alignment of brain wave patterns that seems a bit too intricate to be purely random.

Spend some time looking and you’ll find everything evolution has crafted contains patterns seemingly too intricate to be purely random. In my opinion this is an artifact of our collective laughably poor understanding of the powers of recursive formulae, especially those that have undergone countless rounds of differential optimizations. In fact, the question “could this have been created by evolution” is eerily similar to the halting problem. Suffice to say, our feeble “human intuition” is of little use against true uncomputability.

Less abstractly, it’s been proposed that by flashing through all your memories you might pick up on some prior experience that lets you recover and go on to have some more kids (or provide for existing kids a bit longer)

> But every trait or behaviour that survives on evolutionary timescales does serve (or did serve, in the case of vestigial features) a purpose.

This is in fact not true. There are "coincidences" of evolutionary biology and if there is not selective pressure to change them, they remain for millions of years.

Plenty of traits are inadvertantly selected for, due to being linked to the traits that actually affect fitness under selected.

The probability of a neutral gene becoming fixed is extremely low. It requires a mutation to take a random walk from zero to gene pool saturation. Most neutral traits disappear due to genetic drift, not due to selection pressure. That said, there is no evidence that this is fixed/durable.

I don't think this is a correct model. Because gene mutations and second hand effects aren't truly random. For example, prior mutations which confer some benefit and which are therefore selected for can make certain later neutral mutations more likely.

It is the correct model. You can learn more about it here:

https://www.youtube.com/watch?v=zIftg3cM4BM

You misunderstood me. I didn't mean to say that you had proposed the wrong model for neutral evolution. Rather that direct selective pressure and neutral evolution were not the only possible explanations for how a certain gene sequence might become widespread and therefore your model was incomplete as regards the spread of genes.

Again, there are genetic mutations which make certain other mutations more likely. A beneficial mutation which spreads widely can eventually cause a plurality to carry a gene that is neutral or even harmful by giving it a ride on its own selective pressure.

Furthermore, complex systems are susceptible to emergent behavior. For example, is our brain selected by nature to undergo altered consciousnesses in the presence of some chemical substances? Probably. Should we then believe that nature has "selected" our brains to be altered by every psycho-actice drug that exists? Probably not. Some of these are certainly "happy" accidents by which the chemical function of our brain also happens to be impacted or interfered with by some other chemicals, thus inducing a "high".

This gets a little complicated with the fact that many exogenous psychoactive drugs work because they mimic endogenous chemicals - we have receptors for cannabinoids and opioids because we produce cannabinoids and opioids. The effect of the exogenous versions isn't so much an accident as that some plants produce substances that bind to the same receptors, and we're smart enough to have figured that out and learned to cultivate them.

The argument could be made that this serves some vast evolutionary purpose, but then we're back to inventing gods for ourselves again. (And in any case, such a theory would need also to explain why wasps also enjoy getting drunk, this being after all another example of the same behavior. Evo-psych types being as anthropocentric as they are, this never seems to be addressed, but it needs to be if they want the intellectual coherence to which they so anxiously pretend.)

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