The perplexity comes in with the second question; and it is here that the issue lies between the affirmation and the denial of a second and a supernatural order. We will see, first, how this question is put and treated by Dr. Tyndall, and we will then see what his treatment comes to. Is it true, he asks, as many physicists hold it is, '_that the physical processes are complete in themselves, and would go on just as they do if consciousness were not at all implicated_,' as an engine might go on working though it made no noise, or as a barrel-organ might go on playing even though there were no ear to listen to it? Or do '_states of consciousness enter as links into the chain of antecedence and sequence which gives rise to bodily actions?_' Such is the question in Dr. Tyndall's own phrases; and here, in his own phrases also, comes his answer. '_I have no power_,' he says, '_of imagining such states interposed between the molecules of the brain, and influencing the transference of motion among the molecules. The thing_ eludes all mental presentation. _But_,' he adds, '_the production of consciousness by molecular motion is quite as unpresentable to the mental vision as the production of molecular motion by consciousness. If I reject one result, I reject both. I, however, reject neither, and thus stand in the presence of two Incomprehensibles, instead of one Incomprehensible._'