The phenomenon of consciousness is in one way unique. It is the only phenomenon with which science comes in contact, of which the scientific imagination cannot form a coherent picture. It has a side, it is true, that we can picture well enough--'_the thrilling of the nerves_,' as Dr. Tyndall says, '_the discharging of the muscles, and all the subsequent changes of the organism_.' But of how these changes come to have another side, we can form no picture. This, it is perfectly true, is a complete mystery. And this mystery it is that our modern physicists seize on, and try to hide and lose in the shadow of it a conclusion which they admit that, in any other case, a rigorous logic would force on them. The following is a typical example of the way in which they do this. It is taken from Dr. Tyndall. '_The mechanical philosopher, as such_,' he says, '_will never place a state of consciousness and a group of molecules in the position of mover and moved. Observation proves them to interact; but in passing from one to the other, we meet a blank which the logic of deduction is unable to fill.... I lay bare unsparingly the initial difficulty of the materialist, and tell him that the facts of observation which he considers so simple are "almost as difficult to be seized as the idea of a soul." I go further, and say in effect: "If you abandon the interpretation of grosser minds, who image the soul as a Psyche which could be thrown out of the window--an entity which is usually occupied we know not how, among the molecules of the brain, but which on due occasion, such as the intrusion of a bullet, or the blow of a club, can fly away into other regions of space--if abandoning this heathen notion you approach the subject in the only way in which approach is possible--if you consent to make your soul a poetic rendering of a phenomenon which--as I have taken more pains than anyone else to show you--refuses the ordinary yoke of physical laws, then I, for one, would not object to this exercise of ideality." I say it strongly, but with good temper, that the theologian who hacks and scourges me for putting the matter in this light is guilty of black ingratitude._'