Those who see in the history of law the formal expression of the development of society will be apt to think that the proximate ground of law must be empirical, even when that ground is the fact that a certain ideal or theory of government is generally entertained.  Law, being a practical thing, must found itself on actual forces.  It is quite enough, therefore, for the law, that man, by an instinct which he shares with the domestic dog, and of which the seal gives a most striking example, will not allow himself to be dispossessed, either by force or fraud, of what he holds, without trying to get it back again. 1 Philosophy may find a hundred reasons to justify the instinct, but it would be totally immaterial if it should condemn it and bid us surrender without a murmur.  As long as the instinct remains, it will be more comfortable for the law to satisfy it in an orderly manner, than to leave people to themselves.  If it should do otherwise, it would become a matter for pedagogues, wholly devoid of reality.

I think we are now in a position to begin the analysis of possession.  It will be instructive to say a word in the first place upon a preliminary question which has been debated with much zeal in Germany.  Is possession a fact or a right?  This question must be taken to mean, by possession and right, what the law means by those words, and not something else which philosophers or moralists may mean by them; for as lawyers we have nothing to do with either, except in a legal sense.  If this had always been borne steadily in mind, the question would hardly have been asked.

[214] A legal right is nothing but a permission to exercise certain natural powers, and upon certain conditions to obtain protection, restitution, or compensation by the aid of the public force.  Just so far as the aid of the public force is given a man, he has a legal right, and this right is the same whether his claim is founded in righteousness or iniquity.  Just so far as possession is protected, it is as much a source of legal rights as ownership is when it secures the same protection.

Every right is a consequence attached by the law to one or more facts which the law defines, and wherever the law gives any one special rights not shared by the body of the people, it does so on the ground that certain special facts, not true of the rest of the world, are true of him.  When a group of facts thus singled out by the law exists in the case of a given person, he is said to be entitled to the corresponding rights; meaning, thereby, that the law helps him to constrain his neighbors, or some of them, in a way in which it would not, if all the facts in question were not true of him.  Hence, any word which denotes such a group of facts connotes the rights attached to it by way of legal consequences, and any word which denotes the rights attached to a group of facts connotes the group of facts in like manner.