The structural similarity of men, and their ability to be represented both as ideal, like Leonardo's Vitruvian Man, and as average. Man being the measure of all things, and therefore a sort of standard and interchangeable unit of length, breadth, intelligence, emotion. We could lay them end to end to measure the distance between the continents, the distance to the moon. We could use them to calculate the weight of weather, or to buy things at the grocery. With such an abundance of men, we could gauge anything we chose.