If only we took that as a measure ('is this so important that it can save human lives'), we'd stop the vast majority of testing on animals. So that would be an easy win.

But the lowest hanging fruit is killing animals for meat. Mainly for the joy of having a nice taste in their mouth people who don't really need it eat vast quantities of clever, sentient animals who lead miserable, short lives. The trade off seems easy to me.

My point was more that logically deriving your moral beliefs from reasonable-sounding principles isn't a very reliable method of ethics because you end up at very strange consequences, and if you maintain them because of the logical validity of your chain of reasoning, you quickly become a crackpot: example, anarcho-capitalists, or people who really like Ayn Rand.

I wasn't really looking for an argument about animal rights, though if you really want to get into it, my foundational moral principles are that morality is fundamentally reciprocal in nature, and since animals are incapable of reciprocation, morality doesn't apply to them; a dog isn't immoral for biting a toddler to death (though it may very well be poorly trained), nor am I immoral for eating a delicious double bacon cheeseburger; regardless of the "cleverness" or "sentience" of the cattle and pigs I'm eating, they are fundamentally incapable of morality and so there is no moral significance to anything they experience.

I got your point about the logic sequence, and I meant to convey that while that is something that I found appealing in the book, it is not by far the only foundation for its conclusions.

As for your second paragraph, I don't think it stands up to scrutiny.