The world of objective realities, the world 'out there' could only be in relation to a world of subjective realities, a world 'in here' whose existence is easy to doubt. T e cross-over is by way of the senses, sight, hearing, touch, smell, taste and these not as random occasions of 'data' but as understood categories, or fields, 'spaces', of inner experience. This pre-understanding of possible experience has nothing to do with objective reality and yet neither could exist without the other, and the crossing point is in neither.