BERGER: And you consider all this natural? 
DUD ARD: What could be more natural than a rhinoceros? 
BERGER: Yes, but for a man to turn into a rhinoceros is abnormal beyond question. 
DUD ARD: Well, of course, that's a matter of opinion ... BERGER: It is beyond question, absolutely beyond question! 
DUD ARD: 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. 
BERGER: 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 is move' ... DUD ARD: 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. 
BERGER: [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 anymore. I couldn't care less about Galileo ... I don't give a damn about Galileo. 
DUD ARD: 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. BERGER: [more and more furious] It doesn't prove anything of the sort! It's all gibberish, utter lunacy! 
DUD ARD: There again we need to define exactly what we mean by lunacy ... BERGER: 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?

Rhinoceros / The Chairs / The Lesson