Paulus Gerdes on buttons & Pythagoras
‘Had Pythagoras not … we would have discovered it’. The debate starts. ‘Could our ancestors have discovered the “Theorem of Pythagoras”?’ ‘Did they?’ … ‘Why don’t we know it?’ … ‘Slavery, colonialism …’. By ‘defrosting frozen mathematical thinking’ one stimulates a reflection on the impact of colonialism, on the historical and political dimensions of mathematics (education). (Gerdes, P. (1988). "On Culture, Geometrical Thinking and Mathematics Education." Educational Studies in Mathematics 19(2): 137-162.)
(Gerdes, P. 1999. Geometry from Africa: Mathematical and Educational Explorations. The Mathematical Association of America.)