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Phenomena of the senses are as unlike the causes which set the mechanism of the body in motion, "as the sound of a repeater is unlike the pushing of the spring which gives rise to it"

— Huxley, Thomas H. (1825-1895)

Author

Huxley, Thomas H. (1825-1895)

Work Title

On the Hypothesis that Animals are Automata, and its History

Date

1874

Metaphor

Phenomena of the senses are as unlike the causes which set the mechanism of the body in motion, "as the sound of a repeater is unlike the pushing of the spring which gives rise to it"

Metaphor in Context

Modern physiology amends Descartes' conception of the mode of action of sensory nerves in detail, by showing that their structure is the same as that of motor nerves; and that the changes which take place in them, when the sensory organs with which they are connected are excited, are of just the same nature as those which occur in motor nerves, when the muscles to which they are distributed are made to contract: there is a molecular change which, in the case of the sensory nerve, is propagated towards the brain. But the great fact insisted upon by Descartes, that no likeness of external things is, or can be, transmitted to the mind by the sensory organs; on the contrary, that, between the external cause of a sensation and the sensation, there is interposed a mode of motion of nervous matter, of which the state of consciousness is no likeness, but a mere symbol, is of the profoundest importance. It is the physiological foundation of the doctrine of the relativity of knowledge, and a more or less complete idealism is a necessary consequence of it. For of two alternatives one must be true. Either consciousness is the function of a something distinct from the brain, which we call the soul, and a sensation is the mode in which this soul is affected by the motion of a part of the brain; or there is no soul, and a sensation is something generated by the mode of motion of a part of the brain. In the former case, the phenomena of the senses are purely spiritual affections; in the latter, they are something manufactured by the mechanism of the body, and as unlike the causes which set that mechanism in motion, as the sound of a repeater is unlike the pushing of the spring which gives rise to it.(p. 210)