Are There Limits to Cognition? 119For monism, the percept is determined by the subject.
But, at the same time, the subject has the means in think-
ing to cancel out what it has itself determined.
Metaphysical realists face a further difficulty when
they seek to explain the similarity of the world pictures of
different human individuals. They have to ask them-
selves: “How is it that the world picture that I construct
out of my subjectively determined percepts and concepts
is equivalent to those that other human individuals con-
struct from the same two factors that are subjective to
them? From my own subjective world picture, how can I
draw any conclusions about that of another human be-
ing?” Because people manage to get along with one an-
other in practice, the metaphysical realist believes it
possible to infer the similarity of their subjective world
pictures. From the similarity of these world pictures, a
further inference is then drawn regarding the similarity of
the individual spirits —the “I-in-itself”—underlying the
separate human perceptual subjects.
This kind of conclusion infers, from a sum of effects, the
character of their underlying causes. After a sufficient
number of cases, we believe that we understand the situa-
tion enough to know how the inferred causes will operate
in other cases. We call such an inference an inductive in-
ference. If further observation yields something unexpect-
ed, we will find ourselves forced to modify its results,
because the character of the result is, after all, determined
only by the individual form of our observations. Yet, ac-
cording to the metaphysical realist, this conditional knowl-
edge of causes is perfectly sufficient for practical life.