§ 97 The Animus Possidendi
We shall consider separately these two elements in the conception. And first of the animus possidendi. The intent necessary to constitute possession is the intent to appropriate to oneself the exclusive use of the thing possessed. It is an exclusive claim to a material object. It is a purpose of using the thing oneself and of excluding the interference of other persons. As to this necessary mental attitude of the possessor there are the following observations to be made.
1. The animus sibi habendi is not necessarily a claim of right. It may be consciously wrongful. The thief has a possession no less real than that of a true owner. The possessor of a thing is not he who has, or believes that he has, a right to it, but he who intends to act as if he had such a right. To possession in good faith the law may and does allow special benefits which are cut off by fraud, but to possession as such—the fulfilment of the self-assertive will of the individual—good faith is irrelevant.
2. The claim of the possessor must be exclusive. Possession involves an intent to exclude other persons from the uses of the thing possessed. A mere intent or claim of unexclusive use cannot amount to possession of the material thing itself, though it may and often does amount to some form of incorporeal possession. He who claims and exercises a right of way over another man’s land is in possession of this right of way; but he is not in possession of the land itself, for he has not the necessary animus of exclusion.
The exclusion, however, need not be absolute. I may possess my land notwithstanding the fact that some other person, or even the public at large, possesses a right of way over it. For, subject to this right of way, my animus possidendi is still a claim of exclusive use. I intend to exclude all alien interference except such as is justified by the limited and special right of use vested in others.
3. The animus possidendi need not amount to a claim or intent to use the thing as owner. A tenant, a borrower, or a pledgee may have possession no less real than that of the owner himself. Any degree or form of intended use, however limited in extent or in duration, may, if exclusive for the time being, be sufficient to constitute possession.
4. The animus possidendi need not be a claim on one’s own behalf. I may possess a thing either on my own account or on account of another. A servant, agent, or trustee may have true possession, though he claims the exclusive use of the thing on behalf of another than himself.219
5. The animus possidendi need not be specific, but may be merely general. That is to say, it does not necessarily involve any continuous or present knowledge of the particular thing possessed or of the possessor’s relation to it. A general intent with respect to a class of things is sufficient (if coupled with the necessary physical relation) to confer possession of the individual objects belonging to that class, even though their individual existence is unknown. Thus I possess all the books in my library, even though I may have forgotten the existence of many of them. So if I set nets to catch fish, I have a general intent and claim with respect to all the fish that come therein; and my ignorance whether there are any there or not does in no way affect my possession of such as are there. So I have a general purpose to possess my flocks and herds, which is sufficient to confer possession of their increase though unknown to me. So if I receive a letter, I have forthwith the animus possidendi with respect to its enclosure; and I do not first acquire possession of the cheque that is inside it, when I open the envelope and see it.220 But if, on the other hand, I buy a cabinet believing it to be empty, whereas it contains money hid in a secret drawer, I do not acquire possession of the money until I actually find it; for until then I have no animus with respect to it, either general or specific.221