Operationism

 

Operationism—the view that the meaning of every scientific term must

be specifiable by identifying a definite testing operation

that provides a criterion for its application

 

          main goal of operationism: to ensure the objective testability of all

scientific statements

 

operational definition—the specification of a testing operation that

   provides a criterion for the application of a term

   (e.g., rules of measurement)

 

implication: Operationism is the view that every scientific term

  (observational, theoretical) must have an operational

  definition.

 

Examples of operational definitions—

·       x is electrically charged =df If x is brought near a leaf electroscope, its leaves will diverge.

·       Events E1 and E2 are simultaneous =df If two light signals emitted from E1 and E2 reach an observer stationed halfway between E1 and E2 at the same time.

·       X is an acid =df If blue litmus paper is placed in x, the paper will turn red.

 

Restrictions on operational definitions—

1.    The operation specified in the definition must be capable of being carried out by any competent observer.

2.    The result of the operation must be objectively ascertainable and not dependent on who conducts the operation.

 

Interpretative sentence—a statement that gives (all or part of) the

     meaning of a theoretical term by using

     the pretheoretical terms of the theory

Some implications of operationism:

·       Scientific terms are meaningful only within the range of situations in which the operations specified in their (operational) definitions can be performed.

·       (Therefore) when two operations can be applied for the application of the same term, they must yield the same results. (“requirement of consistency”)

 

Shortcomings of operationism (according to Hempel):

1.    The requirement of consistency calls for a proliferation of theoretical concepts, which deprives each concept of its “systematic import.” (pp. 94-95)

2.    The development of a system of laws, or of a theory, often leads to the modification of the operational criteria originally adopted for the application of scientific terms. (p. 95)

3.    Scientific laws and theories sometimes show that the operational criteria for the application of scientific terms are only approximations and therefore not entirely accurate. (p. 96)

4.    “Systematic import,” no less than “empirical import,” is important for the choice of scientific concepts. (pp. 96-97)

 

Three reasons why scientific concepts are not synonymous with sets of operations: (p. 98)

1.    There are often several alternative criteria of application of a scientific term, based on different sets of operations.

2.    Knowing the theoretical principles in which a scientific term functions is necessary to understand the meaning of that term.

3.    A set of testing operations for a scientific term provides criteria for its application only within a limited range of conditions. Therefore, each set of operations provides only a partial interpretation for the term.

 

 

 

 

Types of Definitions:

A.    explicit:

1.    descriptive—state or describe the accepted meaning(s) of a term already in use, can be true or false

2.    stipulative—assign meanings to terms, cannot be true or false

B.    contextual—specify the meanings of contexts containing the

     terms being defined

 

Interpretative sentences differ from explicit definitions (descriptive, stipulative) in the following respects:

·       Interpretative sentences often give the meaing of scientific terms as contextual definitions rather than as explicit definitions. (p. 98)

·       The requirement of consistency for alternative operational criteria for a scientific term implies an empirical generalization relating the criteria. (p. 98)

 

Criteria of Application for Theoretical Terms: (p. 100)

·       The ways in which sentences containing the terms of a scientific theory can be tested are determined by the bridge principles of the theory.

·       The bridge principles of a scientific theory do not assign any of its theoretical terms some finite number of criteria of application.

·       The bridge principles of a scientific theory provide an indefinite variety of test implications for statements containing its theoretical terms.

 

Hempel’s main conclusion:

·       Theoretical terms are not “individually interpreted by a finite number of operational criteria . . . .” (p. 100)

·       Theoretical terms are interpreted by “a set of bridge principles that . . . provide an indefinite variety of criteria of application [of the terms] by determining an equally indefinite variety of test implications for statements containing one or more of the theoretical terms.” (p. 100)