 Let us now move to another question about Heisenberg’s relations: do they express a principle of quantum theory? Probably the first influential author to call these relations a “principle” was Eddington, who, in his Gifford Lectures of 1928 referred to them as the “Principle of Indeterminacy”. In the English literature the name uncertainty principle became most common. It is used both by Condon and Robertson in 1929, and also in the English version of Heisenberg’s Chicago Lectures (Heisenberg 1930), although, remarkably, nowhere in the original German version of the same book (see also Cassidy 1998). Indeed, Heisenberg never seems to have endorsed the name “principle” for his relations. His favourite terminology was “inaccuracy relations” (Ungenauigkeitsrelationen) or “indeterminacy relations” (Unbestimmtheitsrelationen). We know only one passage, in Heisenberg’s own Gifford lectures, delivered in 1955–56 (Heisenberg 1958: 43), where he mentioned that his relations “are usually called relations of uncertainty or principle of indeterminacy”. But this can well be read as his yielding to common practice rather than his own preference.