Here is the larger context to put this in, related to "normal science".
"Textbooks, more than perhaps any other force in science, represent the bulwarks of existing paradigms. Students of science learn to deal with the world around them in the context of the paradigm they are taught. Ideally, students then grapple with the issues left unresolved within their paradigm and thus continue what Kuhn [Thomas Kuhn] calls the enterprise of "normal science"--"an attempt to force nature into the preformed and relatively inflexible box that the paradigm supplies". In dealing with nature through an existing paradigm, scientists are inherently conservative. They generally shun new theories that may shake their views of the world. According to Kuhn, however, this conservatism is not only inevitable, it is desirable: "By focusing attention upon a small range of relatively esoteric problems, the paradigm forces scientists to investigate some part of nature in a detail and depth that would otherwise be unimaginable". Normal science is essential for fact-gathering that may help confirm, clarify, or even extend paradigms. They also help to match facts with theory, and they even help to make theories more acceptable by, for instance, making them more aesthetically palatable. More fundamentally, normal science can be seen as puzzle-solving, where paradigms determine the parameters and rules for the puzzle. In other words, the paradigm sets the parameters in which scientists may view the world. Researchers must then attempt to solve the puzzles by looking for missing pieces and connecting them into a cohesive whole.
Where Paradigms Fail. This [normal science] period of puzzle solving, however, is often disrupted by discovery, at which point scientists must call into question the rules by which they were solving the puzzle. Restated, "Discovery commences with the awareness of anomaly, i.e. with the recognition that nature has somehow violated the paradigm-induced expectations that govern normal science". Anomaly must emerge within the context of an existing paradigm--otherwise, scientists would be unable to even recognize it."