» Esercizi svolti di Matematica e Fisica

The structure of Scientific Revolutions (Thomas S. Kuhn)

Scientific knowledge is achieved through two complementary modalities:

1. normal mode;
2. revolutionary mode.

In 1, we find a "scientific community" that establishes the existence of general principles and rules. And it is only faith in these principles that is the foundation of further practice. Khun writes:

"A paradigm consists of universally recognized scientific achievements, which, for a certain period of time, provide a model of problems and solutions acceptable to those practicing a certain field of research."

For example, a paradigm may consist of a theory T whose fundamental requirement is the following: T must be better than other competing theories T', T'',... However, T does not necessarily have to explain all the experimental facts within its domain of validity. It's clear that Mode 1 exhibits the highest performance in applied sciences, making it an engineering-type mode.

When, however, "anomalies" arise—i.e., experimental findings that cannot be explained in the normal mode—faith in the paradigm is undermined. The next step is a proliferation of conflicting theories, which, according to Khun, constitute the "core of the crisis." The progressive increase in the number of scholars aware of the existence of anomalies determines the transition from the normal mode to the revolutionary mode. The event that resolves these anomalies is the birth of a new paradigm.