Why were revenge plays so useful for exploring egalitarianism? The answer returns us to mathematics and quantification. Enamored of systems in balance – equations, double-entry bookkeeping, balance of trade, equally matched armies arranged in squares, the body's balanced humors, architectural symmetry – the age was starting to identify fairness with equal-sidedness. And revenge was symmetrical. A perfectly executed condign revenge was beautiful, with the bilateral symmetry of high Renaissance architecture – the Strozzi Palace in Florence, England's Longleat. The medieval word for beautiful, “fair,” came also in the Renaissance to mean “free from … injustice; equitable, legitimate” (OED). Fairness in human conduct was beautiful; and injustice could be re-beautified – made symmetrical, equitable – by compensatory action: an eye for an eye, a tooth for a tooth.

Even such humble texts as William Scott's Essay on Drapery idealized bilateral equality. Trade's purpose was “the good of both parties,” a fair deal for buyer and seller: “If the price exceed the worth of the thing, or the thing exceed the price, the equality of justice is taken away” (18). Fairness meant equal satisfaction: “In the buying and selling of commodities,” a price is “agreed upon between both parties,” reflecting “equality in the value of things” (Malynes, Lex 91). Like an equation, ledger, or symmetrical palace, a mutually satisfactory commercial transaction embodied an ideal of balance.