"To conclude, I argue that the government should not display risk aversion in its behavior. Hence, the proper procedure is to compute the expected values of benefits and costs, and discount them at a riskless rate, contrary to the view of Hirshleifer (1964, p. 85). Suppose the future to be unknown; it is known that one of a set of states will prevail, and their probabilities are known (or believed in). A given state means a complete description of all production possibilities, so that all uncertainties are resolved when the state is known. To summarize some earlier discussions (Arrow, 1964b; Deberu, 1959, chap 7; Hrishleifer, 1964, pp. 80-85), we can achieve an optimal allocation if we imagine markets in all possible commodity-options, a commodity-option being an obligation to deliver a fixed amount of a given commodity if, and only if, a given state prevails."