In real right, Kant investigates the private property of a substance (the soil and the objects on it). In the state of nature the physical or empirical possession of an external object only occurs based on the juridical postulate of the practical reason as a permissive law; otherwise, usable things would be in themselves, or res nullius, but the juridical or intelligible possession depends on the common possession which originates from the soil (and cannot be confounded with primitive communism), to avoid the property to be a relation among people and things, such as what happens in the work theory, because all rights demand a correlated duty, but things cannot have duties towards people, followed by the first occupant's unilateral will to want the object and the advent of an a priori unified will of the people, which only becomes effective in the civil state, the one that is able to generate a reciprocal obligation among all; that is why the intelligible possession is only possible in the civil state, even though the empirical possession of the state of nature has the presumption to become juridical when the entrance in the juridical state occurs and serves by comparison in the wait and preparation of that state.
Kant; Right; Property; Work; Will