nature. If you tickle the foot of a person asleep, and the foot is
withdrawn by simple reflex action, the sleeper is unconscious alike of
the irritation and of the movement, even as the decapitated frog is
unconscious when a drop of nitric acid falls on his back and he lifts up
a leg and rubs the place. In like manner the reflex movements which make
up the life of the lowest animals are doubtless quite unconscious, even
when in their general character they simulate conscious actions, as they
often do. In the case of such creatures, the famous hypothesis of
Descartes, that animals are automata, is doubtless mainly correct. In
the case of instincts also, where the instinctive actions are completely
organized before birth, and are repeated without variation during the
whole lifetime of the individual, there is probably little if any
consciousness. It is an essential prerequisite of consciousness that
there should be a period of delay or tension between the receipt of an
impression and the determination of the consequent movement. Diminish
this period of delay and you diminish the vividness of consciousness. A
familiar example will make this clear. When you are learning to play a
new piece of music on the piano, especially if you do not read music
rapidly, you are intensely conscious of each group of notes on the page,
and of each group of keys that you strike, and of the relations of the
one to the other. But when you have learned the piece by heart, you
think nothing of either notes or keys, but play automatically while your
attention is concentrated upon the artistic character of the music. If
somebody thoughtlessly interrupts you with a question about Egyptian
politics, you go on playing while you answer him politely. That is,
where you had at first to make a conscious act of volition for each
movement, the whole group of movements has now become automatic, and
volition is only concerned in setting the process going. As the delay
involved in the perception and the movement disappears, so does the
consciousness of the perception and the movement tend to disappear.