Several things about this post are unclear or don’t make much sense to me.
What do you mean by “immortal”?
You seem to be responding to the question, “Why didn’t the body just evolve to secrete that [ immortality ] drug itself?” That would imply that “immortality” doesn’t really mean that death is impossible, just that you don’t age. (It’s obvious why absolute immortality can’t evolve.) You could still die from starvation, predation, homicide, war, some sufficiently aggressive disease, some sufficiently severe accident, etc. But much of what you write seems to make no sense once one acknowledges that everyone is still going to die sooner or later, even if later is much later.
I’m also not clear on why the not-really-immortals wouldn’t have children. Indeed, why not just as many children as those who choose not be to immortal? And actually, they could have many, many more children.
You also seem to assume that the not-really-immortals live separately from the mortals. But why? The scenario would seem to be that a drug that prevents aging is discovered. Some people then choose to take it. Some don’t. I don’t see how they end up in different societies.
Considering all this, I don’t see why the decision to take the anti-aging drug is not strictly better from an inclusive fitness point of view. (You can still decide to give your share of food to your children if there’s not enough to go around...)
Sorry if things are not clear. The way I look at it is through the number of generations, which directly determines the evolution rate.
The mortals do one generation every 20-40 years or so
The immortals do much fewer generations: either they don’t reproduce, or they do but then the average age at which they have children is much higher. If you have a child at 10,000 years old, your child (and yourself) will live in the same world as humans who underwent 10,000 years of natural selection.
This is all assuming all those people compete for a shared pool of resources. In the long run, that might make the immortals more likely to die of accidental causes (or diseases due to elevated temperatures, or new viruses etc.). If immortals decide to have children only when they are young, and then stop, then I agree my point doesn’t really apply.
For the second point, it’s not necessary that they live separately (talking about an Imperium may be a bit misleading, sorry). In fact, the more competition, the harder for the immortals to keep up.
I’m still not following you. If the “immortals” start having children at age 20, and have one every 5 years or so for about the next 1000 years (the average age when they get hit by a bus, or whatever), for a total of about 200 children, why isn’t this much better from an evolutionary point of view than being a mortal, who has maybe 10 children?
Sure, the average age at which the immortals have children is much higher. But why does that matter, when they have children at a young age, just like the mortals? They have everything the mortals have, plus more.
Of course, this isn’t sustainable—something will put a stop to it, such as famine. But then, any species that isn’t a total failure cannot sustain its maximum (“when times are good”) reproductive rate. (If its maximum reproduction rate is bare replacement, it won’t be able to recover from some setback, a hurricane or whatever.) If one assumes that “immortality” is cost-free (eg, it doesn’t lead to reduced muscle mass, hence reduced strength, and greater chance of losing a fight), it seems like a definite evolutionary advantage.
There are lot of unstated assumptions involved here. Let’s assume that the tendency to take the anti-aging drug is hereditary—so we’re really discussing whether or not selection will favour the gene for doing this. If the mortals and “immortals” (who actually die after ca. 1000 years) are not reproductively isolated, then it seems quite clear that the gene for taking the drug will be favoured by selection. If one assumes reproductive isolation (as the post seems to), perhaps for social reasons, but that the two groups compete for resources, then the immortal group loses out only if their higher reproductive capacity is outweighed by worse adaptation to changing circumstances. Whether the “immortals” would be less-well adapted will depend on selection effects within that group—if the young immortals out-compete the older immortals, then they adapt just as fast as the mortals. I think you would have a difficult (but maybe not impossible) time finding values for the various within and between group selection effects that would produce a rapid-adaptation advantage for the mortals that would outweigh the huge reproductive advantage of the immortals.
The whole scenario seems rather far from reality to me—talking about evolution implies selection—ie, death or infertility. Assuming the anti-aging drug does not directly affect fertility, I think one can assume that any behavioural trait of low fertility among the immortals will be strongly selected against, after which we’re in the Malthusian state in which the “immortals” often die early from starvation. So the average age when they have children may not be so high after all...
Plus, of course, the scenario assumes a world-changing innovation of an anti-aging drug, but no other world-changing innovations (AI, space travel, …?) that would render the whole discussion irrelevant.
I think I get what you mean by “They have everything the mortals have, plus more” now. The key part is the “200 children” which is of course not sustainable and the answer you and OP have depends on the implicit assumptions of how that is handled.
Several things about this post are unclear or don’t make much sense to me.
What do you mean by “immortal”?
You seem to be responding to the question, “Why didn’t the body just evolve to secrete that [ immortality ] drug itself?” That would imply that “immortality” doesn’t really mean that death is impossible, just that you don’t age. (It’s obvious why absolute immortality can’t evolve.) You could still die from starvation, predation, homicide, war, some sufficiently aggressive disease, some sufficiently severe accident, etc. But much of what you write seems to make no sense once one acknowledges that everyone is still going to die sooner or later, even if later is much later.
I’m also not clear on why the not-really-immortals wouldn’t have children. Indeed, why not just as many children as those who choose not be to immortal? And actually, they could have many, many more children.
You also seem to assume that the not-really-immortals live separately from the mortals. But why? The scenario would seem to be that a drug that prevents aging is discovered. Some people then choose to take it. Some don’t. I don’t see how they end up in different societies.
Considering all this, I don’t see why the decision to take the anti-aging drug is not strictly better from an inclusive fitness point of view. (You can still decide to give your share of food to your children if there’s not enough to go around...)
Sorry if things are not clear. The way I look at it is through the number of generations, which directly determines the evolution rate.
The mortals do one generation every 20-40 years or so
The immortals do much fewer generations: either they don’t reproduce, or they do but then the average age at which they have children is much higher. If you have a child at 10,000 years old, your child (and yourself) will live in the same world as humans who underwent 10,000 years of natural selection.
This is all assuming all those people compete for a shared pool of resources. In the long run, that might make the immortals more likely to die of accidental causes (or diseases due to elevated temperatures, or new viruses etc.). If immortals decide to have children only when they are young, and then stop, then I agree my point doesn’t really apply.
For the second point, it’s not necessary that they live separately (talking about an Imperium may be a bit misleading, sorry). In fact, the more competition, the harder for the immortals to keep up.
I’m still not following you. If the “immortals” start having children at age 20, and have one every 5 years or so for about the next 1000 years (the average age when they get hit by a bus, or whatever), for a total of about 200 children, why isn’t this much better from an evolutionary point of view than being a mortal, who has maybe 10 children?
Sure, the average age at which the immortals have children is much higher. But why does that matter, when they have children at a young age, just like the mortals? They have everything the mortals have, plus more.
Of course, this isn’t sustainable—something will put a stop to it, such as famine. But then, any species that isn’t a total failure cannot sustain its maximum (“when times are good”) reproductive rate. (If its maximum reproduction rate is bare replacement, it won’t be able to recover from some setback, a hurricane or whatever.) If one assumes that “immortality” is cost-free (eg, it doesn’t lead to reduced muscle mass, hence reduced strength, and greater chance of losing a fight), it seems like a definite evolutionary advantage.
I think he is addressing this in the section “Will the Horde win in the long run?” Which point do you disagree with?
There are lot of unstated assumptions involved here. Let’s assume that the tendency to take the anti-aging drug is hereditary—so we’re really discussing whether or not selection will favour the gene for doing this. If the mortals and “immortals” (who actually die after ca. 1000 years) are not reproductively isolated, then it seems quite clear that the gene for taking the drug will be favoured by selection. If one assumes reproductive isolation (as the post seems to), perhaps for social reasons, but that the two groups compete for resources, then the immortal group loses out only if their higher reproductive capacity is outweighed by worse adaptation to changing circumstances. Whether the “immortals” would be less-well adapted will depend on selection effects within that group—if the young immortals out-compete the older immortals, then they adapt just as fast as the mortals. I think you would have a difficult (but maybe not impossible) time finding values for the various within and between group selection effects that would produce a rapid-adaptation advantage for the mortals that would outweigh the huge reproductive advantage of the immortals.
The whole scenario seems rather far from reality to me—talking about evolution implies selection—ie, death or infertility. Assuming the anti-aging drug does not directly affect fertility, I think one can assume that any behavioural trait of low fertility among the immortals will be strongly selected against, after which we’re in the Malthusian state in which the “immortals” often die early from starvation. So the average age when they have children may not be so high after all...
Plus, of course, the scenario assumes a world-changing innovation of an anti-aging drug, but no other world-changing innovations (AI, space travel, …?) that would render the whole discussion irrelevant.
I think I get what you mean by “They have everything the mortals have, plus more” now. The key part is the “200 children” which is of course not sustainable and the answer you and OP have depends on the implicit assumptions of how that is handled.