A simple illustration may serve at once to render this doctrine more easily intelligible, and to show that, if accepted, the doctrine, as it appears to me, terminates the otherwise interminable controversy on the freedom of the will. In an Edison lamp the light which is emitted from the burner may be said indifferently to be caused by the number of vibrations per second going on in the carbon, or by the temperature of the carbon; for this rate of vibration could not take place in the carbon without constituting that degree of temperature which affects our eyes as luminous. Similarly, a train of thought may be said indifferently to be caused by brain-action or by mind-action; for, _ex hypothesi_, the one could not take place without the other. Now, when we contemplate the phenomena of volition by themselves, it is as though we were contemplating the phenomena of light by themselves: volition is produced by mind in brain, just as light is produced by temperature in carbon. And just as we may correctly speak of light as the cause, say, of a photograph, so we may correctly speak of volition as the cause of bodily movement. That particular kind of physical activity which takes place in the carbon could not take place without the light which causes a photograph; and, similarly, that particular kind of physical activity which takes place in the brain could not take place without the volition which causes a bodily movement. So that volition is as truly a cause of bodily movement as is the physical activity of the brain; seeing that, in an absolute sense, the cause is one and the same. But if we once clearly perceive that what in a relative sense we know as volition is, in a similar sense, the cause of bodily movement, we terminate the question touching the freedom of the will. For this question in its last resort--and apart from the ambiguity which has been thrown around it by some of our metaphysicians--is merely the question whether the will is to be regarded as a cause of Nature. And the theory which we have now before us sanctions the doctrine that it may be so regarded, if only we remember that its causal activity depends upon its identity with the obverse aspect known as cerebration, without which identity in apparent duality neither volition nor cerebration could be the cause which in fact they are. It thus becomes a mere matter of phraseology whether we speak of the will determining, or being determined by, changes going on in the external world; just as it is but a matter of phraseology whether we speak of temperature determining, or being determined by, molecular vibration. All the requirements alike of the free-will and of the bond-will hypotheses are thus satisfied by a synthesis which comprises them both. On the one hand, it would be as impossible for an _un_conscious automaton to do the work or to perform the adjustments of a conscious agent, as it would be for an Edison lamp to give out light