ABSTRACT
The construction of a scientific theory is always the building of a more or less refined and consistent system of statements that unifies, enlarges and deepens ideas which, in the pretheoretical stage, had been more or less intuitive, blurred, sketchy and disconnected. Theory construction is so far a more or less spontaneous process; theory formalization, criticism, and demolition involve the deliberate use of definite logical and methodological principles and techniques. Between verbal theories and mathematical models there is a wide range of intermediate degrees of formalization. Whenever dimensional variables do enter a theory, it is often claimed that an additional set of statements must be included in the foundation of the theory. Conceptual means as are employed in theory construction but may not show up in its final presentation are called heuristic ideas. The caloric hypothesis was a heuristic aid in the building of thermodynamics, and so was the homunculus fiction in early genetics.
