Common descent means you can only behave as you do due to historical accidents, which may not hold for much longer as technology improves.
There is an unbroken series running from any human, to any other animal (like a chicken), where each two successive individuals are mother and child. It is merely historical happenstance that most of the individuals, except those at the two ends, are dead: and one that will no longer hold in the future if we defeat death.
If you force your moral theory to evaluate all the individuals along that line—who, again, are not hypotheticals, counterfactuals or future possibilities, but actual historical deceased individuals—then it might say one of two things:
At some point along the line, the mother has moral value, and the child and its descendants do not (or vice versa). Or, at a special point along the line, one daughter has moral value, and her sister does not. That seems arbitrary and absurd.
Moral value gradually changes along the line. People who hold this view differ on whether it ever reaches effectively zero value (in the case of chickens, at least). In this case, you necessarily admit that pre-human individuals (like your ancestor of a few million years ago) have distinctly less-than-human moral value. And you (almost) necessarily admit that, if you extend the line beyond humans into some hypothetical futures, individuals might come to exist who have greater moral value than anyone living today.
The second option flies in the face of your position that:
I think we end up with a much better society if we treat all humans as morally equal
Historically, this merely begs the question: it shifts the argument onto “who is human?” Are blacks? Are women? Are children? Are babies? Are fetuses? Are brain-dead patients? Are mentally or physically crippled individuals? Are factors like (anti-)contraceptives influencing the possibility of future children? Ad infinitum.
So the real value of this statement is merely in the implication that we agree to treat clear non-humans, like chickens, as having no moral value at all. Otherwise we would be forced to admit that some chickens may have more moral value than some proto- or pre-humans.
I don’t think that’s begging the question, as such, simply an appeal to history: We’ve seen what happens if you don’t treat all members of the species Homo Sapiens Sapiens as roughly equal, and it’s not pretty. Today’s society is in fact nicer, along a wide range of fairly concrete axises, and at least some of that can be attributed to increased equality.
My point was that this merely shifted the ground of debate. People began saying that blacks, women, etc. were “not really human” or “sub-human”. Today there are those who think fetuses have the same moral rights as babies, and those who say fetuses are not “really human [individuals]”. And so on.
In other words, it’s a game of definitions and reference class tennis. You should taboo “members of H. Sapiens Sapiens” and specify how you really assign moral value to someone. Your definition should also work with outright non-, pre- and post-humans too, unless you’re willing to say outright that anyone who can’t breed with today’s humans necessarily has zero moral worth.
Steelmaning the argument: “Humans do vary in value, but I should treat all individuals with the power to organize/join political movements and riots in the pursuit of equal rights as equal for wholly practical reasons.”
Common descent means you can only behave as you do due to historical accidents, which may not hold for much longer as technology improves.
There is an unbroken series running from any human, to any other animal (like a chicken), where each two successive individuals are mother and child. It is merely historical happenstance that most of the individuals, except those at the two ends, are dead: and one that will no longer hold in the future if we defeat death.
If you force your moral theory to evaluate all the individuals along that line—who, again, are not hypotheticals, counterfactuals or future possibilities, but actual historical deceased individuals—then it might say one of two things:
At some point along the line, the mother has moral value, and the child and its descendants do not (or vice versa). Or, at a special point along the line, one daughter has moral value, and her sister does not. That seems arbitrary and absurd.
Moral value gradually changes along the line. People who hold this view differ on whether it ever reaches effectively zero value (in the case of chickens, at least). In this case, you necessarily admit that pre-human individuals (like your ancestor of a few million years ago) have distinctly less-than-human moral value. And you (almost) necessarily admit that, if you extend the line beyond humans into some hypothetical futures, individuals might come to exist who have greater moral value than anyone living today.
The second option flies in the face of your position that:
Historically, this merely begs the question: it shifts the argument onto “who is human?” Are blacks? Are women? Are children? Are babies? Are fetuses? Are brain-dead patients? Are mentally or physically crippled individuals? Are factors like (anti-)contraceptives influencing the possibility of future children? Ad infinitum.
So the real value of this statement is merely in the implication that we agree to treat clear non-humans, like chickens, as having no moral value at all. Otherwise we would be forced to admit that some chickens may have more moral value than some proto- or pre-humans.
I don’t think that’s begging the question, as such, simply an appeal to history: We’ve seen what happens if you don’t treat all members of the species Homo Sapiens Sapiens as roughly equal, and it’s not pretty. Today’s society is in fact nicer, along a wide range of fairly concrete axises, and at least some of that can be attributed to increased equality.
My point was that this merely shifted the ground of debate. People began saying that blacks, women, etc. were “not really human” or “sub-human”. Today there are those who think fetuses have the same moral rights as babies, and those who say fetuses are not “really human [individuals]”. And so on.
In other words, it’s a game of definitions and reference class tennis. You should taboo “members of H. Sapiens Sapiens” and specify how you really assign moral value to someone. Your definition should also work with outright non-, pre- and post-humans too, unless you’re willing to say outright that anyone who can’t breed with today’s humans necessarily has zero moral worth.
Sure. That’s a much better way to put it.
Steelmaning the argument: “Humans do vary in value, but I should treat all individuals with the power to organize/join political movements and riots in the pursuit of equal rights as equal for wholly practical reasons.”
That’s a good pragmatic strategy for rulers, but its only moral implication is “might makes right”.
I know that. :(