how many species of animals there are, and whether all animals have the endowments of sense and reason.
there is a certain treatise of aristotle, in which animals are distributed into four kinds, terrestrial, aqueous, fowl, and heavenly; and he calls the stars and the world too animals, yea, and god himself he posits to be an animal gifted with reason and immortal. democritus and epicurus consider all animals rational which have their residence in the heavens. anaxagoras says that animals have only that reason which is operative, but not that which is passive, which is justly styled the interpreter of the mind, and is like the mind itself. pythagoras and plato, that the souls of all those who are styled brutes are rational; but by the evil constitution of their bodies, and because they have a want of a discoursive faculty, they do not conduct themselves rationally. this is manifested in apes and dogs, which have inarticulate voice but not speech. diogenes, that this sort of animals are partakers of intelligence and air, but by reason of the density in some parts of them, and by the superfluity of moisture in others, they neither enjoy understanding nor sense; but they are affected as madmen are, the commanding rational part being defectuous and injured.