We don't sacrifice ourselves for the good of the species. That concept has no intrinsic value in evolutionary biology. We do it for ourselves. We are our genes and our genes will be passed on to our children. By sacrificing for our children, we are also doing something for ourselves.

.. And that's generally the way we behave. What's interesting is that even though we perceive ourselves only as us; as a living expression of a particular constellation of genes, we act in the interest of our genes future survival.

And our genes survival is our own survival, just in more modular terms. We act as if we're people made up of lego. You want the bits you're made up of to go on to make up more people in the future; like your hair colour or a particular brain chemistry or funny looking toes .. and even if your child doesn't have the trait, the gene may be passed on and will be expressed again at some point. While we live for decades, our genes are, in a sense, billions of years old.

I would still argue that it's not necissary we even do it for ourselves. We just do it. We often come up with reasons why we do things later, and different people have different motivations, but all that matters in terms of evolution is that we do it, not that we develop a reasonable argument for why. That's more of a thing that society expects of us to explain our behavior.

Re: ancient genes. Since we (ducks, chickens, spiders, you, and me) can all be traced back to a single ancestor, you can think of your life and experiences as a very small chain in a very long lasting and pervasive process. I always found that to be pretty cool.

How is doing something for your genes doing something for yourself? If sacrificing for your species doesn't make sense then sacrificing for your genes shouldn't either. Neither will help an individual person live on and sacrificing for either has a negative effect on you. What you're talking about sounds more like evolutionary psychology than evolutionary biology, and as far as I know evolutionary psychology borders on pseudo-science at this point.

I know you know vastly more on the subject than I do, so I'm not calling you out, just asking for clarification.

you have to think about how natural selection works. genes are selected in a population based on success. if you are willing to sacrifice yourself for someone who shares a certain gene with you, then that gene can benefit more than if you always act selfishly in that case. think of a parent willing to sacrifice for their children. they can have multiple children that can potentially benefit from this instinct and those children can have a greater change to pass on that gene in even greater numbers. the same doesn't hold true for an instinct to sacrifice for the good of 'the species'. any one particular 'gene' might not benefit from this instinct and so there's no selective pressure for such a gene to develop.

i do disagree with tore that a person is simply their genes and that any given gene's interest is that person's interest. this denies a human being their agency. to counter this point i will offer a simple example. say i have no children and i decide to sterilize myself because i feel having kids would impede on my career/happiness/whatever. am i acting in my own self interest in this case? by the logic that my interests should always necessarily correlate with that of my genes you would have to say no. and yet clearly i have other priorities which are important to me that i am seeking out and so i would say that it only really makes sense from an individual perspective to say yes.

But the reason human society evolved in the first place is because it increases survival odds, which makes it more likely that you'll pass your genes on. Meaning that genes that encourage social cooperation should get passed on. It seems like the same basic evolutionary mechanism to me.

You are right. Our interests that look after our genes of course work at a very basic level. You know this already of course, but your want for sex is a powerful expression of a feeling which will motivate you into perpetuating your genes.

There could be more subtle motivations - you might regret your decision to sterilize yourself in the future, and that could be an influence of genes, directly for a programmed want for children or indirectly through some other social function f.ex, but it would be hard to trace the origin of every notion. Either way, the sum of our behaviours generally lead to children and that generally happens as a result of us doing what we want.

This is what I meant by how our viewpoint is from that of us as unique constellations. We see our needs as selves, but we generally (though not always) act for the betterment of the bits we're made up of. It's an interesting duality of life.

This is all true, Batlord. Humans have evolved to become more social over time because cooperating with others is a great way to ensure your own genes survival (not necessarily the species).

For a silly example about the species view of evolution, let's say we have a tiny population of two households, yours and your neighbour's. You are super nice and your neighbor is super selfish. You two are not related, so there's no kin selection. You are so nice that you give away resources to your neighbour and your neighbour is so selfish he doesn't reciprocate. Your efforts help to bring his selfish genes on and your own genes suffer from it. In the end, only his genes survive in the population.

He's the same species as you, but what value does that have? The answer is basically none. If he's not related to you and does not return the kindness, then by helping your fellow species member, you are actually turning yourself into an evolutionary dead-end. Hence, that behaviour wouldn't evolve, but would get weeded out by natural selection like in the example above.

When you get right down to it, it's a simple matter of cause and consequence. It is superbly formulated in the book The Selfish Gene mentioned by HWB and I think you'd probably love it :)