There are moments in human history when the most arbitrary of numbers take on the weight of divine commandment, and few examples serve this truth better than our modern obsession with ten thousand steps. I find myself walking each morning, my device counting each footfall with mechanical precision, and I cannot help but wonder at the peculiar journey that led us to this particular figure—not nine thousand, not twelve thousand, but precisely ten thousand, as if Moses himself had descended from Sinai with a pedometer in hand.