No one denies that scientists frequently use bodies of knowledge from already-explored fields of inquiry as models as they argue analogically in the attempt to build new theories in other fields; however, there appears to be considerable controversy about the values of the analogical models when once the new theories are complete. One school of thought has it that although acquaintance with a theory's analogical models might serve a useful pedagogical value—helping to introduce the novice to complex ideas—essentially such acquaintance is theoretically superfluous, and is indeed often dangerously misleading. Thus, R.B. Braithwaite cautions us that “The price of the employment of models is eternal vigilance,” and Mario Bunge states flatly that:
In factual science analogy and analogical inference are welcome as theory construction tools. By the same token they are signs of growth, symptoms that the theory is still in the making rather than mature. A mature classical electrodynamics has no need for elastic tubes of force: the field—a non-mechanical substance—suffices for all purposes, the mechanical analogies being regarded as removable appendages.