When we begin to learn to play the piano, we have to devote much time and thought to the adjustment and movement of our fingers and to the interpretation of the vast and complicated multitude of symbols which make up the printed page of music that stands before us.  For a long time, therefore, our attempts are feeble and stammering and they require the full concentrated power of the mind.  Yet a trained pianist will play a new piece of music at sight, and perhaps have so much attention to spare that he can talk with you at the same time.  What an enormous number of mental acquisitions have in this case become almost instinctive or automatic!  It is just so in learning a foreign language, and it was just the same when in childhood we learned to walk, to talk, and to write.  It is just the same, too, in learning to think about abstruse subjects.  What at first strains the attention to the utmost, and often wearies us, comes at last to be done without effort and almost unconsciously.  Great minds thus travel over vast fields of thought with an ease of which they are themselves unaware.  Dr. Nathaniel Bowditch once said that in translating the “Mecanique Celeste,” he had come upon formulas which Laplace introduced with the word “obviously,” where it took nevertheless many days of hard study to supply the intermediate steps through which that transcendent mind had passed with one huge leap of inference.  At some time in his youth no doubt Laplace had to think of these things, just as Rubinstein had once to think how his fingers should be placed on the keys of the piano; but what was once the object of conscious attention comes at last to be well-nigh automatic, while the night of the conscious mind goes on ever to higher and vaster themes.

Let us now take a long leap from the highest level of human intelligence to the mental life of a turtle or a codfish.  In what does the mental life of such creatures consist?  It consists of a few simple acts mostly concerned with the securing of food and the avoiding of danger, and these few simple acts are repeated with unvarying monotony during the whole lifetime of these creatures.  Consequently these acts are performed with great ease and are attended with very little consciousness, and moreover the capacity to perform them is transmitted from parent to offspring as completely as the capacity of the stomach to digest food is transmitted.  In all animals the new-born stomach needs but the contact with food in order to begin digesting, and the new-born lungs need but the contact with air in order to begin to breathe.  The capacity for performing these perpetually repeated visceral actions is transmitted in perfection.  All the requisite nervous connections are fully established during the brief embryonic existence of each creature.  In the case of lower animals it is almost as much so with the few simple actions which make up the creature’s mental life.  The bird known as the fly-catcher no sooner breaks the egg than it will snap at and catch a fly.  This action is not so very simple, but because it is something the bird is always doing, being indeed one out of the very few things that this bird ever does, the nervous connections needful for doing it are all established before birth, and nothing but the presence of the fly is required to set the operation going.