The laws against incest are typical examples of gross intolerance. Most of us feel a sharp physical reaction – something like a shudder – at the idea of connections of this sort; and these reactions we are apt to mistake for profound ethical judgements.
I know all this feeling of disgust and disapprobation because I feel it, not only for incest and things of that sort, but for cheese.
To me the sight of cheese is offensive, the smell shocking, the mere thought disturbing and vexatious: to see people eating it revolts my whole being to its depths and undermines my sense of human dignity.
Yet reason tells me that the eating of cheese is no sin. Reason forbids me to mistake a physical reaction for a moral judgement, which is what every other part of my nature longs to do. Reason overrides prejudice.
The essence of intolerance is the exalting of prejudices into principles, and the imposing of them on other people.
Clive Bell: Civilization. London 1928, Seite 124