There has arisen an ability to see that mutual limitations are required when lives are carried on in proximity; and to see that there necessarily emerge definite sets of restraints applying to definite classes of actions. And it has become manifest to some, though not it seems to many, that there results an _a priori_ system of absolute political ethics—a system under which men of like natures, severally so constituted as spontaneously to refrain from trespassing, may work together without friction, and with the greatest advantage to each and all. “But men are not wholly like-natured and are unlikely to become so. Nor are they so constituted that each is solicitous for his neighbour’s claims as for his own, and there is small probability that they ever will be. Your absolute political ethics is therefore an ideal beyond the reach of the real.” This is true. Nevertheless, much as it seems to do so, it does not follow that there is no use for absolute political ethics. The contrary may clearly enough be shown. An analogy will explain the paradox. There exists a division of physical science distinguished as abstract mechanics or absolute mechanics—absolute in the sense that its propositions are unqualified. It is concerned with statics and dynamics in their pure forms—deals with forces and motions considered as free from all interferences resulting from friction, resistances of media, and special properties of matter. If it enunciates a law of motion, it {223} recognizes nothing which modifies manifestation of it. If it formulates the properties of the lever it treats of this assuming it to be perfectly rigid and without thickness—an impossible lever. Its theory of the screw imagines the screw to be frictionless; and in treating of the wedge, absolute incompressibility is supposed. Thus its truths are never presented in experience. Even those movements of the heavenly bodies which are deducible from its propositions are always more or less perturbed; and on the Earth the inferences to be drawn from them deviate very considerably from the results reached by experiment. Nevertheless this system of ideal mechanics is indispensable for the guidance of real mechanics. The engineer has to deal with its propositions as true in full, before he proceeds to qualify them by taking into account the natures of the materials he uses. The course which a projectile would take if subject only to the propulsive force and the attraction of the Earth must be recognized, though no such course is ever pursued: correction for atmospheric resistance cannot else be made. That is to say, though, by empirical methods, applied or relative mechanics may be developed to a considerable extent, it cannot be highly developed without the aid of absolute mechanics. So is it here. Relative political ethics, or that which deals with right and wrong in public affairs as partially determined by changing circumstances, cannot progress