BERENGER: And you consider all this natural? 

DUDARD: What could be more natural than a rhinoceros? 

BERENGER: Yes, but for a man to turn into a rhinoceros is abnormal beyond question. 

DUDARD: Well, of course, that's a matter of opinion ... 

BERENGER: It is beyond question, absolutely beyond question! 
DUDARD: You seem very sure of yourself. Who can say where the normal stops and the abnormal begins? Can you personally define these conceptions of normality and abnormality? Nobody has solved this problem yet, either medically or philosophically. You ought to know that. 

BERENGER: The problem may not be resolved philosophically -- but in practice it's simple. They may prove there's no such thing as movement ... and then you start walking ... [he starts walking up and down the room] ... and you go on walking, and you say to yourself, like Galileo, 'E pur si muove' ... 

DUDARD: You're getting things all mixed up! Don't confuse the issue. In Galileo's case it was the opposite: theoretic and scientific thought proving itself superior to mass opinion and dogmatism. 

BERENGER: [quite lost] What does all that mean? Mass opinion, dogmatism -- they're just words! I may be mixing everything up in my head but you're losing yours. You don't know what's normal and what isn't any more. I couldn't care less about Galileo ... I don't give a damn about Galileo. 

DUDARD: You brought him up in the first place and raised the whole question, saying that practice always had the last word. Maybe it does, but only when it proceeds from theory! The history of thought and science proves that. BERENGER: [more and more furious] It doesn't prove anything of the sort! It's all gibberish, utter lunacy! 

DUDARD: There again we need to define exactly what we mean by lunacy ... 

BERENGER: Lunacy is lunacy and that's all there is to it! Everybody knows what lunacy is. And what about the rhinoceroses -- are they practice or are they theory?

~ Eugène Ionesco

Thus, by science I mean, first of all, a worldview giving primacy to reason and observation and a methodology aimed at acquiring accurate knowledge of the natural and social world. This methodology is characterized, above all else, by the critical spirit: namely, the commitment to the incessant testing of assertions through observations and/or experiments — the more stringent the tests, the better — and to revising or discarding those theories that fail the test. One corollary of the critical spirit is fallibilism: namely, the understanding that all our empirical knowledge is tentative, incomplete and open to revision in the light of new evidence or cogent new arguments (though, of course, the most well-established aspects of scientific knowledge are unlikely to be discarded entirely).. . . I stress that my use of the term 'science' is not limited to the natural sciences, but includes investigations aimed at acquiring accurate knowledge of factual matters relating to any aspect of the world by using rational empirical methods analogous to those employed in the natural sciences. (Please note the limitation to questions of fact. I intentionally exclude from my purview questions of ethics, aesthetics, ultimate purpose, and so forth.) Thus, 'science' (as I use the term) is routinely practiced not only by physicists, chemists and biologists, but also by historians, detectives, plumbers and indeed all human beings in (some aspects of) our daily lives. (Of course, the fact that we all practice science from time to time does not mean that we all practice it equally well, or that we practice it equally well in all areas of our lives.)

~ Alan Sokal