the last resort always a weapon in the struggle for existence, a means to give to our movements, be they movements in nature or society, the most suitable forms and directions.
"Philosophers have only interpreted the world differently," said Marx. "The great thing, however, is to change it."
3.—The Motives of Self-Maintenance and Propagation.
Both the powers of self-movement and of knowing belong thus inseparably together as weapons in the struggle for existence. The one developed itself along with the other, and in the degree in which these weapons gain in importance in the organism, others, more primitive, lose, being less necessary, as, for example, that of fruitfulness and of vital force. On the other hand, to the degree that these diminish must the importance of the first-named factors for the struggle for life increase, and it must call forth their greater development.
But self-movement and knowledge by no means form by themselves a sufficient weapon in the struggle. What use are to me in this struggle the strongest muscles, the most agile joints, the sharpest senses, the greatest understanding, if I do not feel in me the impulse to employ them to my preservation; if the sight of food or the knowledge of danger leaves me indifferent and awakens no emotion in me? Self-movement and intellectual capacity first then become weapons in the struggle for existence, if with them there arises a longing for the self-preservation of the organism; which brings it about that all knowledge which is of importance for its existence at once produces the will to carry out the movement necessary for its existence, and therewith calls forth the same.
Self-movement and intellectual powers have no importance for the existence of the individual without this instinct of self-preservation, just as this latter again is of no importance without both the former factors. All the three are most intimately bound up with each other. The instinct of self-preservation is the most
