According to Kant, human beings cannot know the ultimate structure of reality. Whilst humans experience the world as having three spatial dimensions and as being extended in time, we cannot say anything about how reality ultimately is, from a god's-eye perspective. From this perspective, the world may be nothing like the way it appears to human beings. We cannot get out of our heads and leave our human perspective on the world to know what it is like independently of our own viewpoint; we can only know about how the world appears to us, not about how the world is in itself. Kant calls the world as it appears to us from our point of view the world of sense or of appearances. The world from a god's-eye perspective is the world of things in themselves or the “world of understanding.”