The impulse of self-preservation is at the basis of all animal life. From the simplest lump of protoplasm constituting a microbe to the highest form of life, such as man, one meets with the same primitive life tendency,—the impulse of self-preservation. Throughout all animal creation one important purpose runs, and that is the preservation of life.

When a creature is launched into the world, it is animated with one central, innate mission,—to live; and to fight for its living. For this purpose,—if purpose it really be, the creature, however small and insignificant, is provided with a rich arsenal of armour for defense and attack. When a biologist demonstrated the anatomical structure of a caterpillar, a bystander exclaimed in surprise: “Why, I always thought that a caterpillar was nothing but skin and squash!”

The simple living creatures, swarming in the waters of stagnant ponds and murky pools, the bits of living matter, inhabiting by the million the little world of a hanging drop of water, are supplied with the most complicated reactions, mechanical and more especially chemical, for the maintenance of their life existence. Simple as a cell, a minute particle of protoplasm, may appear, it is none the less a most wonderful laboratory where toxins, anti-toxins, and an infinite variety of secretions, highly poisonous and protective, are being produced, for the keeping in existence of that insignificant, microscopic bit of living matter. Self-preservation is the central aim of all life-activities.

The tendency of all organic processes is the maintenance of the life of each particular individual organism. It is this aspect that I wish to impress on the minds of my readers. Self-preservation is the nucleus of organic life. It is the mainspring of organic activities and functions. The tendency of life is not the preservation of the species, but solely the preservation of each individual organism, as long as it is in existence at all, and is able to carry on its life processes.

Every living thing, from the ultra-microscopic to the highest and most complex multicellular organism, man included, has only one fundamental tendency, the maintenance and defense of its individual existence. The claim that the individual counts for little or nothing, and that the species is everything, is not true to facts. “Nature cares not for the individual, but for the species” is a glittering generality of a metaphysical character.

It is the maintenance of its individual existence and the struggle for this individuality and its preservation, whether in defense or aggression, that form the main object of organic life in all its aspects. The aim of life activities is the individual, the species is a secondary matter. It is only when we keep this fundamental truth in mind that we begin to understand life in general, and human life in particular.

The struggle for existence of which so much is heard in modern science, theoretical or applied, means really the preservation of the individual organism, or the self-preservation of individuality. We may say that the struggle for existence in the biological and social worlds means nothing else but the Struggle for Individuality.

Wherever the organism forms a whole as to its vitality, whether it be an amoeba or a man, the struggle is for the maintenance of that whole or of that particular individual organism. All the structures and functions go to the preservation of that individuality, or of that individual organic self, constituting the impulse of self-preservation in the total activity of the particular individual organism. The great number of physico-chemical and mechanical processes, adaptations and adjustments of inner structures and functions, as well as the different reactions to the stimuli of external environment, even in the lowest of micro-organisms, are for the whole of the individuality.

When organisms take to forms of social life the fundamental aim is still the protection or self-preservation of the individual. The community is an additional defense of the individual against a hostile environment. Thus the herds of Damara cattle, or of social aggregates of other animals, offer greater protection to each individual animal. The individual wolf running in packs has more power for attack and defense. The individual man has more forces for aggression and for protection by living in a social medium which provides the individual with more sensory organs for observation of danger and with more organs for defense and attack, than in isolated states. The herd, the pack, the horde, the society are for the self-preservation of the individual.

It has been shown on good grounds that the very sense of external reality has become intensified in the individual by his capacity of living in a social aggregate. The social aggregate strengthens each individual member of the group. The individual is not for the group, but the group is for self-preservation of the individual. Should the individual lose his self-protection, or even have his impulse of self-preservation lowered, the whole aggregate faces ultimate destruction. That is why when in a social aggregate the impulse of self-preservation becomes limited, inhibited, and lowered by tyranny of social commandments, society is sure to decline, degenerate, and finally dissolve; or fall a victim to an external invader,—the fate of tribes, communities, and nations in the past and the present. The moving power of life is self-preservation of the individual.

A close study of life in general and of animal life in particular brings one to the inevitable conclusion that life in all its forms has self-preservation as its fundamental principle. Self-preservation is the main impulse, the prime mover of life. The prime mover of life is not the impulse of species preservation, or of sex, but the impulse of self-preservation of the individual organism.

Self-preservation has two aspects, the positive and the negative. In the positive form the primitive impulse is to keep the individual alive, to keep the functions and structure in normal condition, to conduce to the full development and harmonious activity of the individual. The negative form of the preservative impulse is the preservation from injury, degeneration, destruction, and death. This negative aspect of the impulse of self-preservation expresses itself in the higher animals in the form of fear.

The fear instinct is an essential constituent of the impulse of life. We may call the fear instinct the guardian of all sentient being. Wherever there is the least scent or even the least suggestion of danger, there the instinct of fear is aroused. Fear is the companion following close on the heels of the impulse of self-preservation.

Since every animal is always surrounded by enemies, and since every strange thing or strange occurrence is a menace or possible signal of danger, the fear instinct is aroused on all strange occasions. The fear instinct requires the slightest stimulus to start into function.

While most of the instincts require special conditions, and are usually periodic, the fear instinct is ever present and can be awakened on all occasions, and under any circumstances. Anything unfamiliar,—darkness, a state of exhaustion, weakness, fatigue, arouses the fear instinct, startling the animal into running, hiding, crouching, and preparation for attack or defense.

The fear instinct stays with us, and watches over us day and night. It follows us closely in our active, waking life, attends us in our resting hours, and watches over us in our sleeping periods. The fear instinct is the last to fall asleep, and the first to awake. The fear instinct follows us like our shadow, with the only difference that it constantly affects our actions, hardly ever leaves us alone, and keeps steady vigilance over our life activities. The reason for this apparently strange companionship is the fact that the fear instinct is the primitive instinct of the life impulse, the impulse for self-preservation.

The overwhelming intensity of the fundamental impulse of self-preservation is well described by the great writer Dostoevsky, whose insight into the psychology of human life and especially into abnormal mental life transcends that of any other writer: “Where is it I have read that someone condemned to death says or thinks, an hour before his death, that if he had to live on some high rock, on such a narrow ledge that he had only room to stand, and the ocean, everlasting darkness, everlasting solitude, everlasting tempest around him, if he had to remain standing on a square yard of space all his life, a thousand years, eternity, it were better to live so than to die at once! Only to live, to live, and live! Life whatever it may be!”

Just as the touch and pain nerves enmesh closely our body, warning us against hurtful stimulations, so we may say that fear, through our distant receptors of sight, hearing and smell, surrounds us, warning us against enemies, or inimical, suspicious objects, and forces. Were it not for the fear instinct, directly awakened, the animal threatened with danger would not have the time and the strong impulse to get ready for defense or for escape, by running or by hiding.

The fear instinct is of the utmost importance in animal life. Looked at from this standpoint the fear instinct is as important in animal economy as the skin which covers our body, which, by pain and hurts, warns of external injurious objects, and has an important function of warding off incessant invasion of disease-bearing organisms. In nervous ills we find the same fundamental factors:—self-preservation and the fear instinct.