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.

In science novelty emerges only with difficulty, manifested by resistance, against a background provided by expectation.

Communication across the revolutionary divide is inevitably partial.

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.

Research under a paradigm must be a particularly effective way of inducing paradigm change.

Its assimilation requires the reconstruction of prior theory and re-evaluation of prior fact, an intrinsically revolutionary process that is seldom completed a single man and never overnight

Later scientific theories are better than earlier ones for solving puzzles in the often quite different environments to which they are applied. That is not a relativist's position, and it displays the sense in which I am a convinced believer in scientific progress.