Now these questions are all virtually answered in the affirmative by the dualistic theory of Spiritualism. For the Will is here regarded as an agent bound to act in accordance with those conditions of external necessity which dualism recognizes as natural causation. Its internal causation thus becomes but the reflex of external; and the reflection becomes known internally as the consciousness of motive. Hence, the Will cannot be philosophically liberated from the toils of this external necessity, so long as dualism recognizes that necessity as existing independently of the Will, and thus imposing its conditions on volitional activity. But the theory of Monism, by identifying external with internal causation--or physical processes with psychical processes--philosophically saves the doctrine of freedom, and with it the doctrine of moral responsibility. Moreover, it does so without relying upon any precarious appeal to the direct testimony of consciousness itself. As this view of the subject is one by no means easy of apprehension, I will endeavour to unfold it part by part. To begin with, Monism excludes the possibility of volition being determined by cerebration. Let us suppose, for example, that a sequence of ideas, _A, B, C, D_, occurs in the mind, which on its obverse or cerebral aspect may be represented by the sequence _a, b, c, d_. Here the parallelism is not due, as supposed by Materialism, to _a_ determining _Ab_, _b_ determining _Bc_, &c.; it is due to _Aa_ determining _Bb_, _Bb_ determining _Cc_, &c.--the two apparently diverse causal sequences being really but one causal sequence. If the determinist should rejoin that a causal sequence of some kind is all that he demands--that the Will is equally proved to be unfree, whether it be bound by the causal sequence _a, b, c, d_, or by the causal sequence _Aa, Bb, Cc, Dd_--I answer that this is a point which we have to consider by-and-by. Meanwhile I am only endeavouring to make clear the essential distinction between the philosophical theories of Monism and Materialism. And the effect of this distinction is to show that, for the purposes of clear analysis, we may wholly neglect either side of the double reality. If we happen to be engaged on any physiological inquiry, we may altogether neglect the processes of ideation with which any process of cerebration may be concerned; while, if we happen to be engaged upon any psychological inquiry, we may similarly neglect the processes of cerebration with which any process of ideation may be concerned. Seeing that each is equally an index of a common sequence, it can make no difference which of them we take as our guide, although for purposes of practical inquiry it is of course expedient to take the cerebral index when we are dealing with the objective side of the problem, and the mental index when dealing with the subjective. In the following pages, therefore, I shall altogether neglect the cerebral index.