’I am myself inclined (p. 285) to admit unconscious mental modifications, in the only sense in which I can attach any very distinct meaning to them—­namely, unconscious modifications of the nerves.  It may well be believed that the apparently suppressed links in a chain of association, those which Sir W. Hamilton considers as latent, really are so:  that they are not even momentarily felt, the chain of causation being continued only physically—­by one organic state of the nerves succeeding another so rapidly, that the state of mental consciousness appropriate to each is not produced.’

Mr Mill gives various illustrations in support of this doctrine.  He at the same time calls attention to a valuable lecture of Sir W. Hamilton’s, the thirty-second lecture on Metaphysics; especially to the instructive citation from Cardaillac contained therein, noting the important fact, which descriptions of the Law of Association often keep out of sight—­that the suggestive agency of Association is carried on, not by single antecedents raising up single consequents, but by a mass of antecedents raising up simultaneously a mass of consequents, among which attention is very unequally distributed.

We shall say little upon Mr Mill’s remarks on Sir W. Hamilton’s Theory of Causation—­(chap. xvi.).  This theory appears to Mr Mill absurd; while the theory of Mr Mill (continued from Hume, Brown, and James Mill) on the same subject, appears to Sir W. Hamilton insufficient and unsatisfactory—­’professing to explain the phenomenon of causality, but, previously to explanation, evacuating the phenomenon of all that desiderates explanation’—­(p. 295).  For ourselves we embrace the theory of Mr Mill:[13] yet we are aware that the remark just cited from Sir W. Hamilton represents the dissatisfaction entertained towards it by many objectors.  The unscientific and antiscientific yearnings, prevalent among mankind, lead them to put questions which no sound theory of Causation will answer; and they are ready to visit and trust any oracle which professes to deliver a confident affirmative solution of such questions.  Among all the terms employed by metaphysicians, none is used in a greater variety of meanings than the term Cause.

In Mr Mill’s next chapter (xvi.) he comments on Sir W. Hamilton’s doctrine of Concepts or General Notions.  There are portions of this chapter with which we agree less than with most other parts of the volume; especially with his marked hostility to the term Concept, and the reasons given for it, which reasons appear to us not very consistent with what he has himself said in the ‘System of Logic,’ Book IV. chap. ii.  Sec. 1—­3.  The term Concept has no necessary connection with the theory called Conceptualism.  It is equally available to designate the idea called up by a general name, as understood either by Mr Bailey or by James Mill.  We think it useful as an equivalent to the German word Begriff, which sense Sir W. Hamilton has in view when he introduces it, though he does not always adhere to his profession.  And when Mr Mill says (p. 331)—­