The criticism
Some people say: "The sentience standard is anthropocentrism in disguise. You only value sentience because humans have it. It's like valuing animals by how much they resemble us."
How anthropocentrism works
Anthropocentrism takes a trait typical of humans, like the way we reason, and gives animals more importance the more they resemble us in that trait.
Answer 1: sentience has to do with what's at stake
There's a huge difference between using reasoning and using sentience as a standard. The way someone reasons doesn't decide whether they can be harmed. Sentience does. It wasn't picked because it's human, but because it's what makes someone able to be hurt or helped.
Answer 2: the reasoning doesn't start from humans
People who defend sentience don't start by saying "humans matter" and then look for animals that resemble humans. They start by asking "what makes someone able to be harmed?" The answer applies equally to humans and to any other being.
In short
- Anthropocentrism values whatever resembles humans.
- Sentience is chosen because it's relevant to being harmed.
- The reasoning starts from what matters, not from humans.