These two questions have not been always clearly distinguished; the
relativity of knowledge has been sometimes confounded with uncertainty.
The untutored mind is apt to suppose that objects exist independently of
the human faculties, because they really exist independently of the
faculties of any individual. In the same way, knowledge appears to be a
body of truths stored up in books, which when once ascertained are
independent of the discoverer. Further consideration shows us that these
truths are not really independent of the mind; there is an adaptation of
one to the other, of the eye to the object of sense, of the mind to the
conception. There would be no world, if there neither were nor ever had
been any one to perceive the world. A slight effort of reflection enables
us to understand this; but no effort of reflection will enable us to pass
beyond the limits of our own faculties, or to imagine the relation or
adaptation of objects to the mind to be different from that of which we
have experience. There are certain laws of language and logic to which we
are compelled to conform, and to which our ideas naturally adapt
themselves; and we can no more get rid of them than we can cease to be
ourselves. The absolute and infinite, whether explained as self-existence,
or as the totality of human thought, or as the Divine nature, if known to
us at all, cannot escape from the category of relation.

But because knowledge is subjective or relative to the mind, we are not to
suppose that we are therefore deprived of any of the tests or criteria of
truth. One man still remains wiser than another, a more accurate observer
and relater of facts, a truer measure of the proportions of knowledge. The
nature of testimony is not altered, nor the verification of causes by
prescribed methods less certain. Again, the truth must often come to a man
through others, according to the measure of his capacity and education.
But neither does this affect the testimony, whether written or oral, which
he knows by experience to be trustworthy. He cannot escape from the laws