The point of departure for introspective psychology is to be found, so it seems, not in the facts of behavior, but in the distinction between focal and marginal experience. It is on this distinction that the introspective psychologist bases the attempt to give a psychological analysis and description of the contents of experience. To analyze and describe the facts of consciousness is to bring the marginal constituents of experience into the white light of attention. Analysis and description are possible just because experience is so largely a welter of elements that disguise their identity and character. In some way these unrecognized and unidentified elements are constituents of the total experience. To borrow the language of a writer quoted by James, "However deeply we may suppose the attention to be engaged by any thought, any considerable alteration of the surrounding phenomena would still be perceived; the most abstruse demonstration in this room would not prevent a listener, however absorbed, from noticing the sudden extinction of the lights."[40] Or, as James remarks: "It is just like the overtones in music. Different instruments give the 'same note,' namely, various upper harmonics of it which differ from one instrument to another. They are not separately heard by the ear; they blend with the fundamental note and suffuse it, and alter it."[41] Let the attention be directed to these overtones, however, and they at once detach themselves from their surroundings and step forth into the light of day. Even so the ticking of the clock may pass unnoticed in the sense that it is an undiscriminated element in the background of our consciousness; but if the ticking comes to a sudden stop, the feeling of a void in our consciousness proclaims the fact that something has gone out from it.