WHAT IS LOGICAL EMPIRICISM?
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propagation of radiant energy, or the concept of an electric fluid in
early electrical theory. These ontological contents of the hypotheses
must be distinguished from the assertions which the hypotheses make
concerning structural or metrical relations which are testable by em–
pirical operations. The same testable metrical relations could, and in
fact have been, expressed through other scientific metaphors. It would
be useless and ill-advised to attempt the complete elimination of fic–
tive statements from science. But it is necessary to distinguish clearly
between the merely fictive and the cognitive content of scientific
theories.
~
A type of fiction of special importance to science and philosophy
is
one that states a formal meaning in seemingly empirical metaphors.
These have been the source of untold discussions and disputes con–
cerning questions which were unanswerable because, in neglect of
the metaphorical character of the statements, their fictive meanings
were taken for their cognitive content. For example we might con–
sider a doctrine
Of
idealistic metaphysics: "A body is a complex of
sensations." The apparently empirical content of this assertion, sug–
gested by such empirical terms as "body" and "sensation" is entirely
fictive. Regarded as an empirical statement it is devoid of meaning,
for there is no empirical operation whereby its truth may be tested.
It can be shoWn, however, that this metaphysical assertion is so used
that -whenever it is affirmed, the following statement is also affirmed
and conversely: "Every sentence, S, which
cont~ins
a term designating
a body, is the consequence of a class of sentences, C, which contain
no terms designating bodies, but which do contain terms designating
lellSations; and the sentences of the class C are consequences of the
sentence S." This statement expresses the cognitive content of the
metaphysical doctrine which is thereby revealed as a metaphorical
expression of a cognitive meaning. The fictive assertion, as is so often
the case with metaphors, is pithy and direct in contrast with its lum–
bering translation into the purely cognitive form.
It should be noted that the cognitive content of this fictive state–
ment is concerned exclusively with linguistic structures, sentences, and
the logical connections between them. The cognitive content is, in
other words, formal or syntactical. Metaphorical fictive statements
may
be classified as formal or material" depending on whether their
cognitive content is formal or non-formal. In our example the meta–
physical metaphor is a formal statement. But since the formal cog–
nitive content is expressed through empirical metaphors, we describe
the
statement as a formal sentence in the
material mode of language.
The scientific or philosophical use of formal statements in the ma–
taial
mode
is
in itself no more objectionable than the use of meta-
