The first set of regulations coming under this head are those concerning what we distinguish as justice. Individual life is possible only on condition that each organ is paid for its action by an equivalent of blood, while the organism as a whole obtains from the environment assimilable matters that compensate for its efforts; and the mutual dependence of parts in the social organism, necessitates that, alike for its total life and the lives of its units, there similarly shall be maintained a due proportion between returns and labors: the natural relation between work and welfare shall be preserved intact. Justice, which formulates the range of conduct and limitations to conduct hence arising, is at once the most important division of Ethics and the division which admits of the greatest definiteness. That principle of equivalence which meets us when we seek its roots in the laws of individual life, involves the idea of _measure_; and on passing to social life, the same principle introduces us to the conception of equity or _equalness_, in the relations of citizens to one another: the elements of the questions arising are _quantitative_, and hence the solutions assume a more scientific form. Though, having to recognize differences among individuals due to age, sex, or other cause, we cannot regard the members of a society as absolutely equal, and therefore cannot deal with problems growing out of their relations with that precision which absolute equality might make possible; yet, considering them as approximately equal in virtue of their common human nature, and dealing with questions of equity on this supposition, we may reach conclusions of a sufficiently definite kind. This division of Ethics considered under its absolute form, has to define the equitable relations among perfect individuals who limit one another's spheres of action by co-existing, and who achieve their ends by co-operation. It has to do much more than this. Beyond justice between man and man, justice between each man and the aggregate of men has to be dealt with by it. The relations between the individual and the State, considered as representing all individuals, have to be deduced--an important and a relatively difficult matter. What is the ethical warrant for governmental authority? To what ends may it be legitimately exercised? How far may it rightly be carried? Up to what point is the citizen bound to recognize the collective decisions of other citizens, and beyond what point may he properly refuse to obey them?