Nevertheless, neuroscientist Michael Egnor isunimpressed by the morphological similarities. According to Egnor,
We are more different from apes than apes are from viruses. Our difference is a metaphysical chasm. It is obvious and manifest in our biological nature. We are rational animals, and our rationality is all the difference.Human beings, Egnor argues, have mental abilities or powers, that animals simply do not.
Systems of taxonomy that emphasize physical and genetic similarities and ignore the fact that human beings are partly immaterial beings who are capable of abstract thought and contemplation of moral law and eternity are pitifully inadequate to describe man.Humans also have these same material powers, of course, but they have additional powers that are immaterial:
Nonhuman animals such as apes have material mental powers. By material I mean powers that are instantiated in the brain and wholly depend upon matter for their operation. These powers include sensation, perception, imagination (the ability to form mental images), memory (of perceptions and images), and appetite.
Human beings think abstractly, and nonhuman animals do not. Human beings have the power to contemplate universals, which are concepts that have no material instantiation. Human beings think about mathematics, literature, art, language, justice, mercy, and an endless library of abstract concepts.A universal is an abstract concept like humanity or treeness to which particular humans or trees belong. Egnor continues:
Human beings are rational animals.Nonhuman animals operate on the purely material plane. They experience sensations like hunger and pain, but they don't contemplate abstractions like the injustice of suffering or the meaning of their lives.
Human rationality is different because it is immaterial. Contemplation of universals cannot have material instantiation, because universals themselves are not material and cannot be instantiated in matter.
Universals can be represented in matter — the words I am writing in this post are representations of concepts — but universals cannot be instantiated in matter. I cannot put the concepts themselves on a computer screen or on a piece of paper, nor can the concepts exist physically in my brain.
Concepts, which are universals, are immaterial.
It is in our ability to think abstractly that we differ from apes, Egnor argues. It is a radical difference — an immeasurable qualitative difference, not a quantitative difference. It's a difference that creates the metaphysical chasm between humans and other animals.
Egnor concludes with this:
The assertion that man is an ape is self-refuting. We could not express such a concept, misguided as it is, if we were apes and not men.