Whether these background objects really exist can only be made out by studying carefully the changes which result under different conditions, the influences which those loose parts have on the structure of the whole, and the effect of their complete disappearance. I may never really notice a little thing in my room and yet may be aware that it has been taken away. The visual image of it was an element of my mental background, when I was sitting at my desk, but it never before moved to the center of my conscious content. But this center itself is also constantly changing. Sometimes the one, sometimes the other idea may enter into it, but in this alternation that which is not in the focus either remains in consciousness unattended or when it disappears from it it loses its mental character altogether. If I attend a tiresome lecture while my mind is engaged with a practical problem of my own life, there may be a steady rivalry between the words which come with the force of outer stimulus to my brain and make me listen and my inner difficulties which claim my attention. I listen for a while, and then suddenly, without noticing it, my own thoughts may have taken the center of the stage and again without sudden interruption a word may catch my attention. While I was thinking of my own problem the sounds of the lecturer were really outside of my field of attention, yet some remark now pushes itself again into the center. That does not mean that a subconscious mind is listening while my lucid mind was thinking, but it does mean that those words were unattended and remained in the periphery of the field of consciousness. But when some of the sentences stirred up in that peripheral field some important associations, they were strong enough to produce a new motor reaction by which the mental equilibrium became changed again and by which the lecturer overwhelmed my private thoughts. Yet even this state of mind, without any break, can go over into an absolutely physiological process. I may for a while really inhibit the lecturer's voice completely and remain in the thoughts of my own imagination. After a minute or two, the resistance against the acoustical stimulus will certainly be broken and the sound will again enter into my consciousness, but in that interval there was no subconscious and not even any unattended mental function; there was no mental process at all. The sound reached my brain but as the motor setting was adverse, the sounds did not bring about that highest act of physiological transmission which is accompanied by mental contents. Thus it became entirely physiological. Yet of course every word reached my brain and left traces there. If I were hypnotized after the lecture and thus the threshold for the real awakening of brain excitements lowered, it might not be impossible that some of the thoughts of the lecturer which did not enter my consciousness at all, are now afterwards in the hypnotic state stirred up in me.