This from Descent of Man (henceforth DoM). When a dog recognizes another dog a great distance away, it doesn't think of this or that individual, but of dog in general. This example is weak: you might be unable to distinguish whether THIS dog is Fido or Rover, but you are still thinking of THIS dog at this place and time, not of being-a-dog as common to many individuals at different places and times. The latter and not the former constitutes abstract thought. Sorry, Charlie.
Commentary and discussion regarding science, faith and culture by Leo White