If there is difficulty in making a mental adjustment to environment and finding contentment and peace of mind, then the individual is faced by a peculiar problem, he is allowed to continue his physical life, but cannot find mental peace. In order to obtain relief from this intolerable condition, certain devices are unconsciously resorted to. These devices are of the nature of buffers or shock absorbers, and provided the individual does not deviate too much from the normal type, which is adapted to the environment, and that the environment likewise does not differ too much from the type for which the individual was designed, then these devices effectually protect his feelings from the rude shocks of circumstances and enable him to keep his poise and peace of mind. If, however, the strain thrown upon the psychic shock absorber is too great for it adequately to absorb, then the rebound of the buffer-springs throws the machinery of the mind out of gear and makes itself felt in nervous and mental disorders. Like physical disease, mental disease is Nature’s effort at repair which overreaches itself. This, then, is what constitutes mental disease (the organic insanities being excluded from this definition)--the reaction of the mind to what it cannot assimilate. It must not be thought, however, that mental disorder necessarily means insanity. Any faulty functioning of the mind comes under the heading of psycho-pathology, and just as the diseases of the body range from a passing indisposition to some fatal organic disease, so the diseases of the mind range from irritability and forgetfulness to the complete collapse of lunacy. CHAPTER XV CONFLICT As we have already seen, our life is motived by three great instincts. A moment’s thought, however, will cause us to realise that, as these instincts are diverse in their aims, they may sometimes find themselves in opposition to one another; this condition is known to psychologists as CONFLICT, wherein one instinct can only be gratified at the expense of another. For instance, a man may be starving, and be tempted to steal in order to satisfy his hunger. Here we see a conflict between the self-preservation and herd instinct, for if he steals, he may lose his place in the herd, and if he does not steal, he may lose his life, and it is astonishing how many will choose the latter alternative, proving the power and fundamental nature of the herd instinct. The man will be torn two ways, and can only gratify one instinct at the expense of the other. Or, again, he may fall in love with a woman who is denied to him by the marriage laws of his country. Here we see a conflict between the sex instinct and the herd instinct. Or he may fall in love with one whom it would be disadvantageous socially or professionally for him to marry, and here we see a conflict between the sex and self-preservation instincts.