The Structure of Scientific Revolutions

Kuhn emphasizes that paradigms are often very limited when they emerge—they are successful not because they solve everything, but because they provide the tools that future scientists can use to tackle a variety of problems. Normal science is therefore a kind of “mopping-up” of the questions that the paradigm raises, in which scientists try to “force nature into the preformed and relatively inflexible box that the paradigm supplies.”

Again, Kuhn emphasizes that normal science actually discourages novelty and original thinking. But even as Kuhn criticizes normal science, he admits that it allows scientists to solve specific problems in a way that would be impossible without a guiding paradigm. There are three main kinds of knowledge that a paradigm allows its practitioners to focus on.

First, scientists working on normal science must figure out new ways to observe the relevant facts in their paradigm (e.g., star positions in astronomy or wave lengths in physics). To do this, they will create new tools and apparatuses.

Second, scientists try and make nature line up with the paradigm theory’s predictions. Once again, this involves investing in and inventing brand-new machines and technologies to measure various quantities.

Third, scientists look for the actual numbers or rules (“empirical work”) that make a paradigm theory applicable in the real world. Kuhn lists several examples of these kind of constants: there is Avogadro’s number in chemistry, or Boyle’s law in physics (both of which are named after the men who discovered them).

A lot of scientific work in Kuhn’s time involves scientists doing experiments to prove “points of contact between a theory and nature.” This is generally considered to be an elementary form of science, as it merely involves carrying out trials to affirm what a paradigm has already predicted.

Another major part of normal science is responding to the imperfections of the paradigm’s first major discovery (what Kuhn calls “reformulating the paradigm”). For instance, when Newton’s theories about planets’ rotation neglected the gravitational force that planets exert on one another, many world-class mathematicians struggled to come up with a formula to explain this discrepancy. In the process, they discovered mathematical principles that improved many other fields of science and math. Kuhn thus argues that this kind of reformulation—which produces “a more precise paradigm”—is the most theoretical form of normal science.