"practical"
matters, and a sharp distinction maintained between practice and
theoretical knowledge or truth. (See Ch. XX.) The rise of free cities,
the development of travel, exploration, and commerce, the evolution
of new methods of producing commodities and doing business, threw men
definitely upon their own resources. The reformers of science like
Galileo, Descartes, and their successors, carried analogous methods into
ascertaining the facts about nature. An interest in discovery took the
place of an interest in systematizing and "proving" received beliefs.

A just philosophic interpretation of these movements would, indeed, have
emphasized the rights and responsibilities of the individual in gaining
knowledge and personally testing beliefs, no matter by what authorities
they were vouched for. But it would not have isolated the individual
from the world, and consequently isolated individuals--in theory--from
one another. It would have perceived that such disconnection, such
rupture of continuity, denied in advance the possibility of success in
their endeavors. As matter of fact every individual has grown up, and
always must grow up, in a social medium. His responses grow intelligent,
or gain meaning, simply because he lives and acts in a medium of
accepted meanings and values. (See ante, p. 30.) Through social
intercourse, through sharing in the activities embodying beliefs, he
gradually acquires a mind of his own. The conception of mind as a purely
isolated possession of the self is at the very antipodes of the truth.
The self achieves mind in the degree in which knowledge of things
is incarnate in the life about him; the self is not a separate mind
building up knowledge anew on its own account.

Yet there is a valid distinction between knowledge which is objective
and impersonal, and thinking which is subjective and personal. In one
sense, knowledge is that which we take for granted. It is that which is
settled, disposed of, established, under control. What we fully know,
we do not need to think about. In common phrase, it is certain, assured.
And this does not mean a mere feeling of certainty. It denotes not a
sentiment, but a practical attitude, a readiness to act without
reserve or quibble. Of course we may be mistaken. What is taken for
knowledge--for fact and truth--at a given time may not be such. But
everything which is assumed without question, which is taken for granted
in our intercourse with one another