me circumstances it does happen--that the
objective of inquiry is the nature of the geometric form which, when
refracting light, gives rise to these other forms. In this case the
sphere is the thing known, and in this case, the forms of light are
signs or evidence of the conclusion to be drawn. There is no more reason
for supposing that they _are_ (mis)knowledges of the sphere--that the
sphere is necessarily and from the start what one is trying to
know--than for supposing that the position of the mercury in the
thermometer tube is a cognitive distortion of atmospheric pressure. In
each case (that of the mercury and that of, say, a circular surface) the
primary datum is a physical happening. In each case it may be used, upon
occasion, as a sign or evidence of the nature of the causes which
brought it about. Given the position in question, the circular form
would be an intrinsically _unreliable_ evidence of the nature and
position of the spherical body only in case it, as the direct datum of
perception, were _not_ what it is--a circular form.

I confess that all this seems so obvious that the reader is entitled to
inquire into the motive for reciting such plain facts. Were it not for
the persistence of the epistemological problem it would be an affront to
the reader's intelligence to dwell upon them. But as long as such facts
as we have been discussing furnish the subject-matter with which
philosophizing is peculiarly concerned, these commonplaces must be urged
and reiterated. They bear out two contentions which are important at the
juncture, although they will lose special significance as soon as these
are habitually recognized: Negatively, a prior and non-empirical notion
of the self is the source of the prevailing belief that experience as
such is primarily cognitional--a knowledge affair; positively,
_knowledge is always a matter of the use that is made of experienced
natural events_, a use in which given things are treated as indications
of what will be experienced under different conditions.

Let us make one effort more to clear up these points. Suppose it is a
question of knowledge of water. The thing to be known does not present
itself primarily as a matter of knowledge-and-ignorance at all. It
occurs as a stimulus to action and as the source of certain undergoings.
It is something to react to:--to drink, to wash with, to put out fire
with, and also something that reacts unexpectedly to our reactions,
that makes