XV. J THE LAWS OF HABIT. 175 



For the sake of clearness, I have stated the law of the Weaken- 

 weakeniug and destruction of habits by disuse as if it ^^^°^g ^y 

 were an independent law. But in reality it is not so : disuse is a 

 it is a mere case of the elementary law of habit. The general 

 elementary law is, that by acting in any way a habit is 1^^^- 

 formed of acting in that way : and it is a mere case of that 

 law, that by ceasing so to act, a habit is formed of not so 

 acting ; or, what is the same thing in other words, the All actions 

 habit of so acting is lost. The only really elementary 1^^^°?^^^ . 

 laws of habit are these three : that all actions, whether all habits 

 formative, motor, or mental, tend to become habitual ; that hereditary: 

 all habits tend to become hereditary ; and that all habits all liabits 



'' are van- 



are in some degree variable. able. 



As I have stated, the present strength, or what may be 

 called the prominence of a habit, depends on its having 

 been recently exercised ; but its tenacity depends on what 

 is quite different, namely, the length of time (millions of 

 generations, it may be) during which it has been exercised. 

 These simple and well-known truths are little more than 

 obvious corollaries from the elementary laws of habit ; but 

 on them depend some very remarkable and rather intricate 

 interactions between different habitual characteristics. A 

 habit which has been much exercised during a compara- 

 tively short time may be very prominent, but it cannot be 

 very tenacious ; and it may be lost by disuse during a 

 period of time which is too short to produce any per- 

 ceptible effect in destroying a more tenacious, though 

 perhaps less prominent habit. Cases of this kind are no 

 doubt difiicult to identify, but it certainly is possible that 

 new mental and moral habits, amounting to a change of 

 character, may be acquired as a result of education and 

 circumstances, and may afterwards disappear with ad- 

 vancing age and under new circumstances, while the Reappear- 

 original, perhaps hereditary, character reappears. habits ° * 



A tenacious habit may appear to be lost when it is in Latent 

 reality only latent. A latent habit is one which, though ^*^^*'*- 

 not obvious, may at any time reappear ; sometimes spon- 

 taneously, sometimes by placing the organism in the same 

 circumstances as those which produced the habit at first. 



