 Cook Wilson thus believed to have found an answer to the notorious set of regress arguments known as the ‘third man’ in Parm. 132a-143e. (Ryle argued later on that Cook Wilson’s answer would not do, developing his own regress argument against the notion of ‘being an instance of’, that Ryle read Cook Wilson as presupposing, while merely claiming that it is sui generis (Ryle 1971, vol. I, 9–10).)