But still they represent the physical facts so reliably, and their deviations from them correspond so highly, that different subjects in spite of their different standpoints can consider their respective phenomenal worlds as identical, that is, as, for all practical purposes, one and the same objective reality. The question has at least partially been answered by psychophysics, if this term is taken in a sonewhat loose sense. The decisive point is that there is no direct communication between physical objects and percepts corresponding to them, but that between them there is a more or less long and complicated chain of causation whose critical link is the stimulation of receptors, that is, the initial penetration of the organism. This point is decisive. For the only basis of a phenomenal world is the totality of stimulations of millions and millions of receptor cells in their ever-changing distribution, as called forth by the changes in the objects themselves and by changes in the relations between objects and organisms as caused by the subject itself, whether impulsively or intentionally.
Percepts are never structurally identical with the varying configurations on the receptor level.
For these reasons percepts are in decisive characteristics more like objects than like the stimuli intercalated between objects and percepts. The formulations of these authors raise many new and unsolved problems. Therefore the conventional conception is preferable according to which there is neither direct connection nor identity between object and percept. This leaves the basic theoretical question of how and by what factors varying stimulus configurations are transformed into stable percepts. But his arguments are so highly speculative and so far from empirical evidence that in this connection he shall only be mentioned.