Robin Gandy’s “On the Axiom of Extensionality–Part 1”, Journal of Symbolic Logic, Vol. 21, No. 1 (Mar., 1956) quotes Alan Turing using a racist phrase.
Yikes. Those unfamiliar with this particular racist phrase will be disappointed to learn that it’s still current enough in the UK to be used “totally unintentional[ly]”… whatever that means.
Gandy’s paper isn’t the first time I’ve been pulled out of my mathematical/logical/philosophical reverie by racist bullshit. When I was reading Ronald Clark’s The Life of Bertrand Russell, I posted a thread on Twitter of Russell’s many racist utterances, with a selection of three racist Bertrand Russell quotes; two anti-racist quotes repudiate his earlier statements, offering some modest redemption.
I found these episodes of casual, by-the-way racism jarring: they pulled me out of my investment with the material and my ability or even desire to identify with the author.
What’s galling is that Turing “always” spoke of the axiom of extensionality this way; Gandy thought the phrase worth repeating verbatim; the reviewers and editors and publishers thought the phrase acceptable; and those who cite the paper don’t seem to find this footnote worth remarking on. Gandy’s paper is important and widely cited—a foundational resource on extensionality in general, and functional extensionality in particular—but if I refer someone to it, I’m going to let them know to expect a disappointingly racist quote from Turing.