A consideration of these characteristics of habits makes clear its dangers as well as its values.  The fact that habit is based on actual changes which take place in the nervous system, that its foundation is physical, emphasizes its binding power.  Most people in talking and thinking of habit regard it as something primarily mental in nature and therefore believe all that is necessary to break any habit is the sufficient exercise of will power.  But will power, however strong, cannot break actual physical connections, and it is such connections that bind us to a certain line of activity instead of any other, when once the habit is formed.  It is just as logical to expect a car which is started on its own track to suddenly go off on to another track where there is no switch, as to expect a nerve current traveling along its habitual conduction unit to run off on some other line of nervous discharge.  Habit once formed binds that particular line of thought to action, either good or bad.  Of course habits may be broken, but it is a work of time and must result from definite physical changes.  Every habit formed lessens the likelihood of any other response coming in that particular situation.  Every interest formed, every act of skill perfected, every method of work adopted, every principle or ideal accepted, limits the recognition of any other possible line of action in that situation.  Habit binds to one particular response and at the same time blinds the individual to any other alternative.  The danger of this is obvious.  If the habits formed are bad or wasteful ones, the individual is handicapped in his growth until new ones can be formed.  On the other hand, habit makes for limitation.

Despite these dangers, habit is of inestimable value in the development of both the individual and the human race.  It is through it that all learning is possible.  It makes possible the preservation of our social inheritance.  As James says, “Habit is the enormous fly-wheel of society, its most precious conservative agent.”  Because of its power of limitation it is sometimes considered the foe of independence and originality, but in reality it is the only road to progress.  Other things being equal, the more good habits a person has, the greater the probability of his doing original work.  The genius in science or in art or in statesmanship is the man who has made habitual many of the activities demanded by his particular field and who therefore has time and energy left for the kind of work that demands thinking.  Habit won’t make a genius, but all men of exceptional ability excel others in the number and quality of their habits in the field in which they show power.  As the little child differs from the adult in the number and quality of his habits, so the ordinary layman differs from the expert.  It is scarcity, not abundance, of habits that forces a man into a rut and keeps him mediocre.  Just as the three year old, having taken four or five times as long as the adult to dress himself, is tired out at the end of the task, so the amateur in literature or music or morals as compared with the expert.  The more habits any one has in any line, the better for him, both from the standpoint of efficiency and productivity, provided that the habits are good and that among them is found the habit of breaking habits.