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Kuhn posited a process to explain the persistence of incorrect ideas, and the seemingly rapid and sudden abandonment of these ideas when they finally are rejected.
People tend to believe in what they know, and science is basically conservative. A current "paradigm" or theory is difficult to dislodge. It takes either a large volume of evidence, or a particularly powerful single piece of evidence to overturn major scientific theories (scientific revolution). When this occurs, it is called a "paradigm shift".
 Paradigm shifts and the demarcation problem
The concept of paradigm shifts offers one means of resolving the demarcation problem. Kuhn drew a division between sciences in a pre-paradigm state and those in a post-paradigm state, i.e. having a unifying theory or school of thought. Before a consensus is built around a single paradigm, the field is not a "true science" but a protoscience at best or a pseudoscience at worst.
 Misuses and criticisms
Creationists, New Agers, and other pseudoscientists often reference Kuhn when citing the supposed "fragility" of scientific theories, although for some reason, the only theory that is found to be fragile is evolution, rather than something truly fragile like Intelligent design. Supporters of vitalism and the like often pull the same crap; it amounts to nothing more than trying to move the goalposts or special pleading, claiming that some area (God, the soul, whatever) is off-limits to scientific inquiry.
During the period of the so-called Science Wars, some advocates of "science studies" abused the term paradigm shift to justify their conclusions as a kind of scientific knowledge. ("Science studies" was a program of
postmodernist pseudointellectual hogwash treating scientific knowledge as a socially constructed cultural-literary text, to be creatively critically deconstructed so as to satisfy the deconstructors' sociopolitical agenda to reveal its underpinnings as an instrument of oppression. No, really, you can't make this stuff up; Poe's law applies to loony-left whackadoodles, too.)
 History of science
Some scientists and historians of science have criticized the concept on various grounds, a common one being that paradigm shifts don't occur in the revolutionary sense as often as Kuhn claimed, but happened more gradually.
- Stanford Encyclopedia of Philosophy: Scientific Revolutions, The Incommensurability of Scientific Theories