Science is a system of relations. Poincaré, saying so, says also, "It is before all a classification, a manner of bringing together facts which appearances separate, though they are bound together by some natural and hidden kinship...."It is in the relations alone that objectivity must be sought; it would be vain to seek it in beings considered as isolated from one another...."External objects...for which the word object was invented, are really objects and not fleeting and fugitive appearances, because they are not only groups of sensations, but groups cemented by a constant bond. It is this bond, and this bond alone, which is the object in itself, and this bond is a relation. "Therefore, when we ask what is the objective value of science, that does not mean: Does science teach us the true nature of things? but it means: Does it teach us the true relations of things?"