Remark III. Sensuous knowledge represents things only in the way that they affect our senses. Appearances, not things as they exist in themselves, are known through the senses. Space, time, and all appearances in general are mere modes of representation. Space and time are ideal, subjective, and exist "a priori" in all of our representations. They apply to all of the objects of the sensible world because these objects exist as mere appearances. Such objects are not dreams or illusions, though. The difference between truth and dreaming or illusion depends on the connection of representations according to rules of true experience. A false judgment can be made if we take a subjective representation as being objective. All the propositions of geometry are true of space and all of the objects that are in space. Therefore, they are true of all possible experience. If space is considered to be the mere form of sensibility, the propositions of geometry can be known "a priori" concerning all objects of external intuition.