Next he inquires "whether we have any higher warrant for this fundamental belief than the warrant of conscious induction," and writes as follows of logical necessity (pp. 172-179): "The consciousness of logical necessity, is the consciousness that a certain conclusion is implicitly contained in certain premises explicitly stated. If, contrasting a young child and an adult, we see that this consciousness of logical necessity, absent from the one is present in the other, we are taught that there is a _growing up_ to the recognition of certain necessary truths, merely by the unfolding of the inherited intellectual forms and faculties. To state the case more specifically:--before a truth can be known as necessary, two conditions must be fulfilled. There must be a mental structure capable of grasping the terms of the proposition and the relation alleged between them; and there must be such definite and deliberate mental representation of these terms as makes possible a clear consciousness of this relation.... Along with acquirement of more complex faculty and more vivid imagination, there comes a power of perceiving to be necessary truths, what were before not recognized as truths at all.... All this which holds of logical and mathematical truths, holds, with change of terms, of physical truths. There are necessary truths in Physics for the apprehension of which, also, a developed and disciplined intelligence is required; and before such intelligence arises, not only may there be failure to apprehend the necessity of them, but there may be vague beliefs in their contraries.... But though many are incapable of grasping physical axioms, it no more follows that physical axioms are not knowable _a priori_ by a developed intelligence, than it follows that logical relations are not necessary, because undeveloped intellects cannot perceive their necessity.