Here’s a great story for TOK: “Nazi perfect Aryan poster child was Jewish.” We certainly don’t need additional evidence to debunk racist and nationalist classifications of humanity, but the bitter ironies of this particular story do make it hit home. How we classify – how we group our particular observations into general categories, and then how we use those categories as conceptual generalizations – is a recurrent theme in TOK, involving most ways of knowing (especially intuition and reason, language, sense perception) and all areas of knowledge (all of them, but notably the natural and human sciences and history). As this story brings home, there are plenty of implications for how we group people, then attach values and emotions.  (For more on this topic, see  IB TOK Course Companion, pp. 211-214)

References 

Eileen Dombrowski, Lena Rotenberg, Mimi Bick.  Theory of Knowledge Course Companion, 2013 edition.  Oxford University Press, 2013. https://global.oup.com/education/product/9780199129737?region=international

“Nazi perfect Aryan poster child was Jewish”, The Telegraph, July 2, 2014. http://www.telegraph.co.uk/news/worldnews/europe/germany/10938062/Nazi-perfect-Aryan-poster-child-was-Jewish.html