EXCERPT In his first Critique, Immanuel Kant orients reason in relation to the planetary surface, and thus to human bipedalism. He writes that, although the earth appears to one’s immediate senses as a flat surface extending indefinitely to the horizon, we can nevertheless, ‘in accordance with a priori principles’, know that it is a ‘sphere’ with ‘diameter’, ‘magnitude’ and ‘limits’. Clearly intending a comparison between the two, the philosopher then adds that ‘our reason’ is, in identical fashion, ‘not like an indeterminably extended plane’ but ‘must rather be compared to a sphere’…