It is possible to have any external object of my will as mine. In other words, a maxim to this effect--were it to become law - that any object on which the will can be exerted must remain objectively in itself without an owner, as res nullius, is contrary to the principle of right. For an object of any act of my will, is something that it would be physically within my power to use. Now, suppose there were things that by right should absolutely not be in our power, or, in other words, that it would be wrong or inconsistent with the freedom of all, according to universal law, to make use of them. On this supposition, freedom would so far be depriving itself of the use of its voluntary activity, in thus putting useable objects out of all possibility of use. In practical relations, this would be to annihilate them, by making them res nullius, notwithstanding the fact that acts of will in relation to such things would formally harmonize, in the actual use of them, with the external freedom of all according to universal laws. Now the pure practical reason lays down only formal laws as principles to regulate the exercise of the will; and therefore abstracts from the matter of the act of will, as regards the other qualities of the object, which is considered only in so far as it is an object of the activity of the will. Hence the practical reason cannot contain, in reference to such an object, an absolute prohibition of its use, because this would involve a contradiction of external freedom with itself. An object of my free will, however, is one which I have the physical capability of making some use of at will, since its use stands in my power (in potentia). This is to be distinguished from having the object brought under my disposal (in potestatem meam reductum), which supposes not a capability merely, but also a particular act of the free-will.
But in order to consider something merely as an object of my will as such, it is sufficient to be conscious that I have it in my power. It is therefore an assumption a priori of the practical reason to regard and treat every object within the range of my free exercise of will as objectively a possible mine or thine. his postulate may be called "a permissive law" of the practical reason, as giving us a special title which we could not evolve out of the mere conceptions of right generally. And this title constitutes the right to impose upon all others an obligation, not otherwise laid upon them, to abstain from the use of certain objects of our free choice, because we have already taken them into our possession. Reason wills that this shall be recognised as a valid principle, and it does so as practical reason: and it is enabled by means of this postulate a priori to enlarge its range of activity in practice. Any one who would assert the right to a thing as his must be in possession of it as an object. Were he not its actual possessor or owner, he could not be wronged or injured by the use which another might make of it without his consent. For, should anything external to him, and in no way connected with him by right, affect this object, it could not affect himself as a subject, nor do him any wrong, unless he stood in a relation of ownership to it.
