But the signs are due to anthropomorophism. We are equating it
  to us. That's our limitation. It's fine, for practical purposes,
  to believe that ants don't have awareness. But until 1984, it
  was still ok for doctors to believe that babies run on instinct
  and don't feel pain. They didn't respond the way adults do. It
  was a practical matter. Same could eventually equally be found
  true for other things. We've been dreadfully wrong before and
  we'll do so again, and we're likely doing it now. Science is far
  from over.