To know evil For to know evil, for them, was to know it not by pure intelligence by by experience. Charles Williams, The Mind of the Maker evil
Economy of material and labor Whatever the comparative merits of [various bed framing methods], what is clear from Aristotle's Mechanica is that economy of material, and labor, was as much an issue in ancient times as it is now. Henry Petroski, The Evolution of Useful Things The requirements of economyThe art of not constructing simplicity