The origins and immediate vitality of the left/right divide which emerged in French revolutionary politics from 1789 can only be understood against the background of a much older classification dynamic based on the primacy of the right hand, first described by Robert Hertz in 1909. This dynamic infused political thinking first in Versailles and since 1815 in democracies throughout the world. In the process, the classical left/right polarity acquired a new dimension: the complementary notions of ‘accepting’ and ‘questioning’ the existing social order. An essential feature of both the age-old classical polarity and the ensuing political polarity is that they are intimately bound up with local and evolving social contexts: there is no single content-based definition of left and right. As long as the majority of us are predisposed to use our right hand when acting in the world, ‘left versus right’ will remain the most important political antithesis in western-type democracies.