The question in this text
Why do we accept doing things to animals that we would never accept doing to people? A common answer is: "because they're not human." This text asks whether that answer actually explains anything.
"Humans matter because they're human"
Imagine someone saying: "Only frogs deserve respect, because they're frogs." You'd ask: "But what's so special about being a frog?" If the person just repeated "being a frog," they wouldn't have explained anything.
The same thing happens with humans. Saying "humans matter more because they're human" just repeats the conclusion. What's missing is why belonging to the human species would change how much a pain or a death counts.
"Everyone looks after their own"
Another version says: "It's not that humans are special; it's that everyone should favor their own species." Here, the special thing would be belonging to the same species as the person deciding.
The problem is the same: it still doesn't explain why that would matter. The author makes a comparison. A racist could say: "I'm not saying my race is better; I just think everyone should favor their own race." Almost everyone sees that this is unfair. Swapping "race" for "species" doesn't fix the problem.
What now?
The text points out that there are other attempts to justify how animals are treated, like appealing to intelligence, the soul, or tradition. They come up in the next chapters.
In short
- "Because they're human" isn't a reason; it's the conclusion said again.
- "Everyone favors their own" has the same flaw as racism and sexism.
- A good reason has to show why the difference matters.