nd engaged in universals, and in those things which exist of
necessity, and since there are _principles of things demonstrable and of
every science_ (for science is joined with reason), it will be neither
science, nor art, nor prudence, which discovers the principles of
science;... it must therefore be (nous) pure intellect," or the
intuitive reason.[681] He also characterizes these principles as
_self-evident_. "First truths are those which obtain belief, not through
others, but through themselves, as there is no necessity to investigate
the '_why_' in scientific principles, but each principle ought to be
credible by itself."[682] They are also _necessary_ and _eternal_.
"Demonstrative science is from necessary principles, and those which are
_per se_ inherent, are necessarily so in things."[683] "We have all a
conception of that which can not subsist otherwise than it does.... The
object of science has a necessary existence, therefore it is _eternal_.
For those things which exist in themselves, by necessity, are all
eternal."[684] But whilst Aristotle admits that there are "immutable and
first principles,"[685] which are not derived from sense and
experience--"principles which are the foundation of all science and
demonstration, but which are themselves indemonstrable,"[686] because
self-evident, necessary, and eternal; yet he furnishes no proper account
of their genesis and development in the human mind, neither does he
attempt their enumeration. At one time he makes the intellect itself
their source, at another he derives them from sense, experience, and
induction. This is the defect, if not the inconsistency, of his
method.[687]

[Footnote 680: "Post. Analytic," bk. i. ch. xxxi.]

[Footnote 681: "Ethics," bk. vi. ch. vi.]

[Footnote 682: "Topics," bk. i. ch. i.]

[Footnote 683: "Post. Analytic," bk. i. ch. vi.]

[Footnote 684: "Ethics," bk. vi. ch. iii.]

[Footnote 685: Ibid., bk. vi. ch. xi.]

[Footnote 686: "Post. Analytic," bk. i. ch. iii.]

[Footnote 687: Hamilton attempts the following mode of reconciling the
contradictory positions of Aristotle:

"On the supposition of the mind virtually containing, antecedent to all
experience, certain universal principles of knowledge, in the form of
certain necessities of thinking; still it is only by repeated and
comparative experiments that we compass the certainty; on the one hand,
that such and such cognitions can not but be thought as necessary,
native gene