The varied and often strict limitations of property mentioned above are all determined by some thought, wise or foolish, of social expediency.
Different parts of wealth may be treated in different ways: there may be private property in wagons, and public property in roads; private property in houses, and public property in forests; private property in automobiles, and public property in railway carriages.

But any rule of property, like any other workable human law, must be applicable to all individuals that meet the conditions.
The very acceptance of the theory of social expediency implies the need of frequent readjustment of the institution of private property.
The essential thought in the various attacks on the institution of property is that, because it either causes or makes possible the inequality of incomes, it is not socially expedient.

Private property, as it is found to-day, is complicated by many historical accidents.
Survivals of ancient injustice and relics of feudal institutions that rest on no vital reason remain in our new country as well as in the older ones.

The limits of property in many respects are determined not according to the logic of expediency, but by the social inertia which often governs successive generations.
The question is raised in many minds: If private property is not an absolute right, what shall be its limits?
What changes should be made in it?
These questions put the greatest economico-political problem of our day, one that contains within it, indeed, many minor problems.

A number of these will receive attention in the following pages.
Sec.9.