In the above questions a materialist would substitute ‘brain and nervous system’ for ‘character,’ and thereby obtain a clearer notion; but I have avoided using terms which suggest materialistic assumptions, because Determinism by no means involves Materialism. For the present purpose the difference is unimportant. The substantial dispute relates to the completeness of the causal dependence of any volition upon the state of things at the preceding instant, whether we specify these as ‘character and circumstances,’ or ‘brain and environing forces.’[59] On the Determinist side there is a cumulative argument of great force. The belief that events are determinately related to the state of things immediately preceding them is now held by all competent thinkers in respect of all kinds of occurrences except human volitions. It has steadily grown both intensively and extensively, both in clearness and certainty of conviction and in universality of application, as the human mind has developed and human experience has been systematised and enlarged. Step by step in successive departments of fact conflicting modes of thought have receded and faded, until at length they have vanished everywhere, except from this mysterious citadel of Will. Everywhere else the belief is so firmly established that some declare its opposite to be inconceivable: others even maintain that it always was so. Every scientific procedure assumes it: each success of science confirms it. And not only are we finding ever new proof that events are cognisably determined, but also that the different modes of determination of different kinds of events are fundamentally identical and mutually dependent: and naturally, with the increasing conviction of the essential unity of the cognisable universe, increases the indisposition to allow the exceptional character claimed by Libertarians for the department of human action.