In this, again, is the basis for the distrust with which we meet testimony concerning hearsay. For we feel uncertain in the mere absence of the person whose conversation is reported, since his value can not be determined. But a part of the mistrust lies in the fact that it is not vision but the perennially half-doubted hearing that is in issue. Lies are assigned mainly to words; but there are lies which are visual (deceptions, maskings, illusions, etc.). Visual lies are, however, a diminishing minority in comparison with the lies that are heard. The certainty of the correctness of vision lies in its being tested with the sense of touch,--i.e. in the adaptation of our bodily sense to otherwise existing things. As Helmholtz says, “The agreement between our visual perceptions and the external world, rests, at least in the most important matters, on the same ground that all our knowledge of the actual world rests on, upon the experience and the lasting test of their correctness by means of experiments, i.e., of the movements of our bodies.” This would almost make it seem that the supreme judge among the senses is the touch. But that is not intended; we know well enough to what illusions we are subject if we trust the sense of touch alone. At the same time we must suppose that the question here is one of the nature of the body, and this can be measured only by something similar, i.e., by our own physical characteristics, but always under the control of some other sense, especially the sense of sight. The visual process itself consists, according to Fischer, “of a compounded series of results which succeed each other with extraordinary rapidity and are causally related. In this series the following elements may principally be distinguished. (1) The physico-chemical process. (2) The physiologico-sensory. (3) The psychological. (4) The physiologico-motor. (5) The process of perception.”