 In the 1960s and early 1970s, this thesis was advanced rather more aggressively by a number of authors, including especially David Finkelstein and Hilary Putnam, who argued that quantum mechanics requires a revolution in our understanding of logic per se. According to Putnam, “Logic is as empirical as geometry. … We live in a world with a non-classical logic” ([1968] 1979: 184).