straightforward and confident answer, we shall be well launched on the
study of philosophy--for philosophy is merely the attempt to answer
such ultimate questions, not carelessly and dogmatically, as we do in
ordinary life and even in the sciences, but critically, after
exploring all that makes such questions puzzling, and after realizing
all the vagueness and confusion that underlie our ordinary ideas.

In daily life, we assume as certain many things which, on a closer
scrutiny, are found to be so full of apparent contradictions that only
a great amount of thought enables us to know what it is that we really
may believe. In the search for certainty, it is natural to begin with
our present experiences, and in some sense, no doubt, knowledge is to
be derived from them. But any statement as to what it is that our
immediate experiences make us know is very likely to be wrong. It
seems to me that I am now sitting in a chair, at a table of a certain
shape, on which I see sheets of paper with writing or print. By
turning my head I see out of the window buildings and clouds and the
sun. I believe that the sun is about ninety-three million miles from
the earth; that it is a hot globe many times bigger than the earth;
that, owing to the earth's rotation, it rises every morning, and will
continue to do so for an indefinite time in the future. I believe
that, if any other normal person comes into my room, he will see the
same chairs and tables and books and papers as I see, and that the
table which I see is the same as the table which I feel pressing
against my arm. All this seems to be so evident as to be hardly worth
stating, except in answer to a man who doubts whether I know anything.
Yet all this may be reasonably doubted, and all of it requires much
careful discussion before we can be sure that we have stated it in a
form that is wholly true.