This is a sensible question to ask. It could be argued that there is enough chemistry on the IB syllabus to occupy 240 hours (150 hours at Standard Level) of teaching without adding anything extra. In any case, TOK is not examined in the final chemistry examination papers so why bother?It is worth bearing in mind a quote from Georg C Lichtenberg (1742-1799) who was a professor in Germany in the eighteenth century.