The original and the copy
It seems that in terms of natural language everybody knows what a fake, a forgery or false document is. At most, one admits that it is frequently difficult to recognize a forgery as such, but one relies on experts, that is, on those who are able to recognize forgeries simply because they know how to tell the difference between a fake and its original.
Eco, U. (1992)., The original and the copy, in F. Varela & J. Dupuy (eds.), Understanding origins, Dordrecht, Springer, pp. 273-303.
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