History of the paradigm shift

Psychologist Jean Piaget saw children's development as a series of separate stages marked by periods of adjustments. Inspired partly by Piaget, Thomas Kuhn - a physicist, philosopher, and historian of science -proposed two kinds of scientific change:

• Incremental developments in the course of "normal science."
• Scientific revolutions that accentuate the more stable phases.

He proposed that scientific revolutions are not a matter of incremental progress; they involve "paradigm shifts."