A third equivalent of duty is borrowed from sensibility and not, like the preceding, from intelligence and activity. It’s the growing fusion of sensibilities, and the ever increasing sociable character of elevated pleasures, from which results a kind of duty or superior necessity which pushes us naturally and rationally towards others. By virtue of evolution, our pleasures grow and become increasingly impersonal; we cannot experience enjoyment within our selves as if on a deserted isle. Our milieu, to which we better adapt ourselves every day, is human society, and we can no more be happy outside of this milieu than we can breathe outside the air. The purely selfish happiness of certain Epicureans is a chimera, an abstraction, an impossibility; the true human pleasures are all more or less social. Pure egoism, rather than being an affirmation of the self, is a mutilation of the self.
A child saw a butterfly poised on a blade of grass; the butterfly had been made numb by the north wind. The child plucked the blade of grass, and the living flower that was at its tip, still numb, remained attached. He returned home, holding his find in his hand. A ray of sunlight broke through, striking the butterfly’s wing, and suddenly, revived and light, the living flower flew away into the glare. All of us, scholars and workers, we are like the butterfly: our strength is made of a ray of light. Not even: of the hope of a ray. One must thus know how to hope; hope is what carries us higher and farther. “But it’s an illusion!” What do you know of this? Should we not take a step for fear that one day the earth will slide away from under our feet? Looking far into the past or the future is not the only thing; one must look into oneself. One must see there the living forces that demand to be expended, and we must act.
We can judge ourselves and our ideal by posing this question: For what idea, for what person would I be ready to risk my life? He who cannot answer such a question has a vulgar and empty heart. He is incapable of feeling or doing anything grand in life, since he is unable to go beyond his individuality. He is impotent and sterile, dragging along his selfish ego like the tortoise its shell. On the contrary, he who has present in his spirit the idea of death for his ideal seeks to maintain this ideal at the height of this possible sacrifice. He draws from this supreme risk a constant tension and an indefatigable energy of the will. The only means of being great in life is having the consciousness that you will not retreat before death.
Sacrifice, Pages Choisies des Grands Écrivains (1895).
Guyau places at the basis of his ethics the conception of life in the broadest sense of the word. Life manifests itself in growth, in multiplication, in spreading. Ethics, according to Guyau, should be a teaching about the means through which Nature's special aim is attained, -the growth and the development of life. The moral element in man needs, therefore, no coercion, no compulsory obligation, no sanction from above; it develops in us by virtue of the very need of man to live a full, intensive, productive life. Man is not content with ordinary, commonplace existence; he seeks the opportunity to extend its limits, to accelerate its tempo, to fill it with varied impressions and emotional experiences. And as long as he feels in himself the ability to attain this end he will not wait for any coercion or command from without. "Duty," says Guyau, is "the consciousness of a certain inward power, by nature superior to all other powers. To feel inwardly the greatest that one is capable of doing is really the first consciousness of what it is one's duty to do."