telligibly or erroneously, or even both; and why science in a free
society can no longer be regarded as the esoteric bailiwick of an
atypical band of devotees. In short, if the citizenry of the so-called
free world are to influence constructively their moral, political,
economic and physical destinies in which science will play an
ever-increasing role, they will need to understand both what
science is and is not, and what it can and cannot do.

This volume attempts to outline the essential features of the
scientific approach. It attempts to synthesize and coordinate in
nontechnical form the essential elements of two major fields of
study: the logic and philosophy, and the methods, of science. It
is not, however, intended to serve as a substitute for a scholarly
treatment of those fields. Rather, it has been written for the po-
tential reader who is seriously concerned about, the logical struc-
ture and method of science but who does not have the time or the
background to pursue these fields intensively.

The style perhaps demands a word of explanation. The writer
has attempted to lower (if not actually eliminate) the semantic
and conceptual barrier which often separates the lay reader
from the literature of science. The absence of footnotes, for
example, is purposive; and is justified on two counts: (1) The
materials herein presented are accepted as a matter of fact well
established in the common domain of scholarship, and therefore
do not require substantiation by reference to particular authori-
tative sources. For this reason, (2) parenthetical remarks or defini-
tions are included within the appropriate portions of the text in
order to promote unhampered reading and clear understanding.

In spite of the conscientious attempt to employ words pre-
cisely, this objective has not always been achieved in the pages
to follow. The literature of science is not yet highly standardized.
The same term is often used in different ways by various writers
or occasionally even by the same writer. The terms validity and
reliability, for example, mean one thing to a logician but an-
other to a statistician. Among the more common examples of
key terms in the literature of science which are employed in a
variety of ways are: valid,true,reliable,verify,hypothesis,theory,
law,principle,axiom,postulate,proof. Whenever demanded for

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