Descartes knew that many of the actions performed by the human body are not the result of conscious choice, and that some of them are in direct contravention of the will’s commands.  The eye protects itself by dropping its lid, when the hand is brought suddenly before it; the foot jerks away from the heated object which it has accidentally touched.  The body was seen to be a mechanism relatively independent of the mind, and one rather complete in itself.  Joined with a soul, the circle of its functions was conceived to be widened; but even without the assistance of the soul, it was thought that it could keep itself busy, and could do many things that the unreflective might be inclined to attribute to the efficiency of the mind.

The bodies of the brutes Descartes regarded as mechanisms of the same general nature as the human body.  He was unwilling to allow a soul to any creature below man, so nothing seemed left to him save to maintain that the brutes are machines without consciousness, and that their apparently purposive actions are to be classed with such human movements as the sudden closing of the eye when it is threatened with the hand.  The melancholy results of this doctrine made themselves evident among his followers.  Even the mild and pious Malebranche could be brutal to a dog which fawned upon him, under the mistaken notion that it did not really hurt a dog to kick it.

All this reasoning men have long ago set aside.  For one thing, it has come to be recognized that there may be consciousness, perhaps rather dim, blind, and fugitive, but still consciousness, which does not get itself recognized as do our clearly conscious purposes and volitions.  Many of the actions of man which Descartes was inclined to regard as unaccompanied by consciousness may not, in fact, be really unconscious.  And, in the second place, it has come to be realized that we have no right to class all the actions of the brutes with those reflex actions in man which we are accustomed to regard as automatic.

The belief in animal automatism has passed away, it is to be hoped, never to return.  That lower animals have minds we must believe.  But what sort of minds have they?

It is hard enough to gain an accurate notion of what is going on in a human mind.  Men resemble each other more or less closely, but no two are precisely alike, and no two have had exactly the same training.  I may misunderstand even the man who lives in the same house with me and is nearly related to me.  Does he really suffer and enjoy as acutely as he seems to? or must his words and actions be accepted with a discount?  The greater the difference between us, the more danger that I shall misjudge him.  It is to be expected that men should misunderstand women; that men and women should misunderstand children; that those who differ in social station, in education, in traditions and habits of life, should be in danger of reading each other as one reads a book in a tongue imperfectly mastered.  When these differences are very great, the task is an extremely difficult one.  What are the emotions, if he has any, of the Chinaman in the laundry near by?  His face seems as difficult of interpretation as are the hieroglyphics that he has pasted up on his window.