d
its place in his plan.

All of which proves that our knowledge is not necessarily useless
because it is rather dim and vague. It is one thing to use a mental
state; it is another to have a clear comprehension of just what it is
and of what elements it may be made up. The plain man does much of his
thinking as we all tie our shoes and button our buttons. It would be
difficult for us to describe these operations, but we may perform them
very easily nevertheless. When we say that we _know_ how to tie our
shoes, we only mean that we can tie them.

Now, enough has been said in the preceding sections to make clear that
the vagueness which characterizes many notions which constantly recur
in common thought is not wholly dispelled by the study of the several
sciences. The man of science, like the plain man, may be able to use
very well for certain purposes concepts which he is not able to analyze
satisfactorily. For example, he speaks of space and time, cause and
effect, substance and qualities, matter and mind, reality and
unreality. He certainly is in a position to add to our knowledge of
the things covered by these terms. But we should never overlook the
fact that the new knowledge which he gives us is a knowledge of the
same kind as that which we had before. He measures for us spaces and
times; he does not tell us what space and time are. He points out the
causes of a multitude of occurrences; he does not tell us what we mean
whenever we use the word "cause." He informs us what we should accept
as real and what we should repudiate as unreal; he does not try to show
us what it is to be real and what it is to be unreal.

In other words, the man of science _extends_ our knowledge and makes it
more accurate; he does not _analyze_ certain fundamental conceptions,
which we all use, but of which we can usually give a very poor account.

On the other hand, it is the task of _reflective thought_, not in the
first instance, to extend the limits of our knowledge of the world of
matter and of minds, but rather _to make us more clearly conscious of
what that knowledge really is_. Philosophical reflection takes up and
tries to analyze complex thoughts that men use daily without caring to
analyze them, indeed, without even realizing that they may be subjected
to analysis.

It is to be expected that it should impress many of those who are
introduced to it for the first time as rather a fantastic creation of
problems tha