Particularly in the exact sciences, the investigator has turned from
the special problems to the philosophical foundations with ever
clearer consciousness and energy. Whatever one may judge in detail
of the results of these researches, there can be no doubt that the logi-
cal problem has thereby been greatly and directly advanced. I
have, therefore, sought to base the following exposition upon the
historical development of science itself and upon the systematic
presentation of its content by the great scientists. Although we
cannot consider all the problems that arise here, nevertheless, the
special logical point of view which they represent must be carried
through and verified in detail. What the concept is and means in
its general function can only be shown by tracing this function
through the most important fields of scientific investigation and
representing it in general outline.

The problem receives new meaning when we advance from purely
logical considerations to the conception of knowledge of reality.
The original opposition of thought and being breaks up into a number
of different problems, which are, nevertheless, connected and held in
intellectual unity by their common point of departure. Whenever,
in the history of philosophy, the question as to the relation of thought
and being, of knowledge and reality, has been raised, it has been
dominated from the first by certain logical presuppositions, by cer-
tain views about the nature of the concept and judgment. Every
change in this fundamental view indirectly produces a complete
change in the way in which the general question is stated. The
system of knowledge tolerates no isolated "formal" determination
without consequences in all the problems and solutions of knowledge.
The conception, therefore, that is formed of the fundamental nature
of the concept is directly significant in judging the questions of fact
which are generally considered under "Criticism of Knowledge,"
( "Erkenntniskritik") or "Metaphysics." The transformation which
these questions undergo when regarded from the general point of
view that is gained by criticism of the exact sciences and the new
direction which their solution takes, Part II of the book attempts to
show. Both parts, though seemingly separate in content, are united,
nevertheless, in a philosophical point of view; both attempt to repre-
sent a single problem which has expanded from a fixed center, drawing
ever wider and more concrete fields into its circle.

ERNST CASSIRER.

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