In Defense of Operationalism

Operationalism (aka "operationism") posits that we don't know the "meaning" of an experimental result unless we define what we "mean" in terms of the operations comprising the experiment.  For instance, one might measure length with a yardstick in one experiment, and with a tape measure in another experiment.  These are different operations providing different "meanings" for length.

The critics of operationalism obviously have a point when they say that "length" is a concept that is independent of whether you use a yardstick or tape measure.  Indeed, it is trivially obvious.

However, what they fail to grasp is that concepts about nature, like "length", are components of theory.  Theories of nature are, by definition, prior to the experiments that test their predictions.  Any non-trivial theory about nature has infinitely many theorems, hence infinitely many experiments that may test their predictions.  Indeed, natural science would not otherwise be generally useful.  So the fact that there are infinitely many operations that measure "length" is a trivial consequence of theories of nature. 

What is not trivial about operationalism is that it takes seriously the sin qua non of natural science:

Replication

An experiment must be replicable if it is to be considered part of science.  Scientific publications provide the "recipe" to perform experiments.  This "recipe" is the series of operations that establish the experimental conditions and take measurements.  In such a "recipe" it is generally a bad idea to elide details of the original experiment, such as which instruments were used and what one did with those instruments.  Indeed, it is a good idea to keep the actual physical instruments around in the event that a discrepancy in replication may be traced back to some peculiar property of the instruments used in the original experiment.  This includes such things as the identity of the scientists performing the operations, and their institutional context.

All operationalism is really saying is that replication is necessary to scientific meaning.