To win through, by means of unprejudiced observation, to the recognition of this truth of the intuitive essence of thinking requires an effort. But without this effort we shall not succeed in clearing the way for a theory of the psycho-physical organisation of man. We recognise that this organisation can produce no effect whatever on the essential nature of thinking. At first sight this seems to be contradicted by patent and obvious facts. For ordinary experience, human thinking occurs only in connection with, and by means of, such an organisation. This dependence on psycho-physical organisation is so prominent that its true bearing can be appreciated by us only if we recognise, that in the essential nature of thinking this organisation plays no part whatever. Once we appreciate this, we can no longer fail to notice how peculiar is the relation of human organisation to thought. For this organisation contributes nothing to the essential nature of thought, but recedes whenever thought becomes active. It suspends its own activity, it yields ground. And the ground thus set free is occupied by thought. The essence which is active in thought has a two-fold function: first it restricts the human organisation in its own activity; next, it steps into the place of that organisation. Yes, even the former, the restriction of human organisation, is an effect of the activity of thought, and more particularly of that part of it which prepares the manifestation of thinking. This explains the sense in which thinking has its counterpart in the organisation of the body. Once we perceive this, we can no longer misapprehend the significance for thinking of this physical counterpart. When we walk over soft ground our feet leave deep tracks in the soil. We shall not be tempted to say that the forces of the ground, from below, have formed these tracks. We shall not attribute to these forces any share in the production of the tracks. Just so, if with open minds we observe the essential nature of thinking, we shall not attribute any share in that nature to the traces in the physical organism which thinking produces in preparing its manifestation through the body. [3]