Knowledge, Reality, and Value Book Club Replies, Part 5

Here’s my last round of response to reader comments.  I’m on vacation now, but in early September I’ll post one last reply to Huemer’s replies to me, then give the author the last word.


Even if we assign very low probability that insects feel pain and they feel significantly less pain, there are something like 10^18 insects so insect suffering is a massive problem. Nematodes have nociceptors and there are 4*10^19, which is 57 billion for every human. I do not know exactly how but I imagine human beings could be causing massive amounts of suffering to these tiny creatures for trivial reasons all the time.


Having children is not trivial but it would seem there is a moral obligation not to reproduce if there is a risk your child may not be a vegan. It would be the same as the obligation not to reproduce if your children would have a decent chance of being mass murderer. Even vegan children would cause animal suffering as noted above.

Yes, vegans should be anti-natalist.

If you turn the dial of animal concern up too high then saving lives may be unethical. Imagine saving the life of a mass murderer. If I give money to help those in developing countries by giving them malaria nets or vaccines, they could be meat eaters or at least start eating meat 20 years from now when their country is more developed. Turn up the dial more and it might be morally praiseworthy to kill meat eaters. Turn the dial up higher and all human life is inflicting too much suffering on animals; if we were provided the chance, we should kill all human life.

Harsh but fair.

It seems like vegans keep the dial turned pretty high but not quite high enough to start doing really crazy stuff. Where is the line between “trivial”, “moderately trivial” and “unnecessary” or “not completely necessary.” I can’t stomach the idea of having no concern for animals but I can’t see good reason to exclude possibly insects, nematodes, fish, vermin and so forth. And their suffering accumulates. However, doing so seems really really counter intuitive.

Which is why I’m so baffled that the world’s greatest ethical intuitionist would be so sympathetic to vegan premises.

B K:

Since intelligence doesn’t appear to be binary but rather a continuous gradient, and if, as a matter of physics and computer science, there is no hard upper ceiling on intelligence, or if the ceiling is arbitrarily high, those aliens might be hundreds, thousands, millions, billions, or trillions of times smarter than we are. The intelligence difference between them and us could in principle be much greater than the difference between us and cows, pigs, chimpanzees etc.

From the perspective of ‘intelligence is what makes suffering morally bad’ premise, it seems like the only way to say that the aliens above are morally wrong is to posit some threshold of intelligence above which no matter how much more intelligent the aliens are, it is wrong for them to cause great suffering for trivial reasons on those who are merely above the threshold.


I looked at the prior debate, and he actually did bite the bullet which you suggest in your second-to-last paragraph; i.e., he agreed that moral worth is proportional to intelligence, and hence there could (theoretically) be a creature which is so intelligent that it would be entitled to torture and kill us to avoid so much as a stubbed toe.

Actually, I believe I explicitly denied the view that pgbh acribes to me.  I reproduced Huemer’s graph, and said, “Your graph accurately describes my view.”  B K says this is a “lame response,” but I don’t know any way to make it sound less lame.


Killing Banthas, on the other hand, is no big deal, because they’re just alien animals.

This is a bit of a shift in goal posts. Huemer isn’t talking about merely “killing” animals, he’s talking about keeping them in conditions of constant suffering for their entire existence, so responding with examples of animals being killed after living normal lives is a red herring.

Just change the statement to “The suffering of Banthas, on the other hand, is no big deal, because they’re just alien animals,” and my claim works about as well.

I am puzzled by the big distinction many vegans make between killing and causing suffering.  “It’s not morally wrong to kill X, even though he wants to live” strongly suggests that the well-being of X is morally of little importance.

Because “intelligence” is roughly synonymous with “learning ability.”  And since human babies go from knowing zero languages to one language in a couple of years, one can plausible say that they are in fact highly intelligent.

That doesn’t follow. This demonstrates that babies later gain learning ability, and will thus later become intelligent, but that doesn’t entail that babies therefore are highly intelligent in the present sense. That makes no more sense that saying that since babies will go from being almost completely immobile to walking and running within a couple years, it’s  plausible to say babies are in fact highly mobile.

It’s possible, of course, that babies have very low intelligence for months 0-6, and then become highly intelligent, which allows them to learning language.  But a creature that quickly goes from knowing zero languages to one language must have had high learning ability before the language acquisition occurred.  I suppose you could experimentally test this by seeing if babies who hear no language for their first six months acquire language as quickly as babies who hear language from birth.  But my general sound is sound.


Brian, you say that animal welfare has moral import, though a lot less than human welfare. However, your arguments suggest that concerns for animal welfare place no moral constrains on human behavior. What activity involving animals do you think it is morally wrong, if any, and why?

I morally oppose the factory farming of primates, if such exists.

Thanks to everyone for your comments!

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Author: Bryan Caplan

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