Are We Automata?

If we take the actions of lower animals and the actions of lower ganglia in higher animals, what strikes us most in them is the determinateness with which they respond to a given stimulus. The addition of the cerebral hemispheres immediately introduces a certain incalculableness into the result, and this incalculableness attains its maximum with the relatively enormous brain-convolutions of man. In the beheaded frog the legs twitch as fatally when we touch the skin with acid as do a jumping-jack's when we pull the string. The machinery is as narrow and perfect in the one case as in the other. Even if all the centres above the cord except the cerebral hemispheres are left in place, the machine-like regularity of the animal's response is hardly less striking.