The transition between competing paradigms cannot be made a step at a time, forced by logic and neutral experience. Like the gestalt switch, it must occur all at once (though not necessarily in an instant) or not at all.

Rather than being an interpreter, the scientist who embraces a new paradigm is like the man wearing inverting lenses.

All significant breakthroughs are break -“withs” old ways of thinking.

Probably, the single most prevalent claim advanced by the proponents of a new paradigm is that they can solve the problems that led the old one to a crisis.

Groups do not have experiences except insofar as all their members do. And there are no experiences... that all the members of a scientific community must share in the course of a [scientific] revolution. Revolutions should be described not in terms of group experience but in terms of the varied experiences of individual group members. Indeed, that variety itself turns out to play an essential role in the evolution of scientific knowledge.

What a man sees depends both upon what he looks at and also upon what his previous visual-conceptual experience has taught him to see.

Every important idea in science sounds strange at first.