if we repair to our
libraries what disagreement do we discover! Where is a certainly true
answer found? Apart from abstract propositions of comparison (such as
two and two are the same as four), propositions which tell us nothing
by themselves about concrete reality, we find no proposition ever
regarded by any one as evidently certain that has not either been
called a falsehood, or at least had its truth sincerely questioned by
some one else. The transcending of the axioms of geometry, not in play
but in earnest, by certain of our contemporaries (as Zoellner and
Charles H. Hinton), and the rejection of the whole Aristotelian logic
by the Hegelians, are striking instances in point.

No concrete test of what is really true has ever been agreed upon.
Some make the criterion external to the moment of perception, putting
it either in revelation, the _consensus gentium_, the instincts of the
heart, or the systematized experience of the race. Others make the
perceptive moment its own test,--Descartes, for instance, with his
clear and distinct ideas guaranteed by the veracity of God; Reid with
his 'common-sense;' and Kant with his forms of synthetic judgment _a
priori_. The inconceivability of the opposite; the capacity to be
verified by sense; the possession of complete organic unity or
self-relation, realized when a thing is its own other,--are standards
which, in turn, have been used. The much {16} lauded objective
evidence is never triumphantly there, it is a mere aspiration or
_Grenzbegriff_, marking the infinitely remote ideal of our thinking
life. To claim that certain truths now possess it, is simply to say
that when you think them true and they _are_ true, then their evidence
is objective, otherwise it is not. But practically one's conviction
that the evidence one goes by is of the real objective brand, is only
one more subjective opinion added to the lot. For what a contradictory
array of opinions have objective evidence and absolute certitude been
claimed! The world is rational through and through,--its existence is
an ultimate brute fact; there is a personal God,--a personal God is
inconceivable; there is an extra-mental physical world immediately
known,--the mind can only know its own ideas; a moral imperative
exists,--obligation is only the resultant of desires; a permanent
spiritual principle is in every one,--there are only shifting states of
mind; there is an endless chain of causes,--there is an abs