In the examination of Sir William Hamilton's Philosophy, he still more emphatically expressed his dissent from Schelling, Cousin, and every school of idealism, rejecting the doctrine of intuitive knowledge; taking the eternal ground from beneath the ideas of the Infinite and Absolute; sharply questioning the well-conceded interpretations of consciousness; resolving the "first principles" into mental habits; and even going so far as to doubt whether twice two necessarily made four.[3] [3] Vol. 1, page 89, 90. The system of Spencer and other expositors of the doctrine of evolution is, in its general features and its ultimate tendency, too familiar to be stated. Its hostility to the intuitive philosophy must be obvious even to unpractised minds. The atomic theory of the constitution of matter, which, in one or another form, is accepted by the majority of scientific men, gives ominous prediction of disaster to every scheme that is built on the necessary truths of pure reason. But the philosophers of the experimental school are by no means in accord among themselves, on a matter so cardinal as the relation of mind to organization. In the latest edition of the Logic, Mill repeats the language used in the first:[4] "That every mental state has a nervous state for its immediate antecedent, though extremely probable, cannot hitherto be said to be proved, in the conclusive manner in which this can be proved of sensations; and even were it certain, yet every one must admit that we are wholly ignorant of the characteristics of these nervous states; we know not, and have no means of knowing, in what respect one of them differs from another.... The successions, therefore, which obtain among mental phenomena, do not admit of being deduced from the physiological laws of our nervous organization." "It must by no means be forgotten that the laws of mind may be derivative laws resulting from laws of animal life, and that their truth, therefore, may ultimately depend on physical conditions; and the influence of physiological states or physiological changes in altering or counter-acting the mental successions, is one of the most important departments of psychological study. But on the other hand, to reject the resource of psychological analysis, and construct the theory of mind solely on such data as physiology affords at present, seems to me as great an error in principle, and an even more serious one in practice. Imperfect as is the science of mind, I do not scruple to affirm that it is in a considerably more advanced state than the portion of physiology which corresponds with it; and to discard the former for the latter appears to me to be an infringement of the true canons of inductive philosophy." [4] Logic, p. 591. Amer. Edition. In a previous chapter[5] Mill had said: