Nussbaum does this rhetorical move that is irritating. She first says:
humans are not so special for having language:
language is not that important to being a human
other animals have language too!
humans are not so special for having metacognition:
metacognition is not that important for being human, most of our lives are not devoted to that
other animals have metacognition too!
In both cases, she doesn't seem to realize that the two parts of the argument pull in opposite directions. If metacognition is not all that important for human, then why stress that animals have it too? Also, there is a matter of degree. We are not supposed to notice that human language is far more complex than any other zoosemiotics.
It also comes in when she is talking about animals and refers to their "leisure time." The phrase is grating in this context, because it taking something defined in particular ways in some human cultures (probably not all of them) and then treating it as a zoological absolute.
I've seen other people deploy this move before. You could say: systems of writing are not such a great measure of civilization. Then, turn around and say, other people have systems of writing too, not just Europeans! In the second argument, you are asserting the value of something that you denied in the first part of the argument.