L. Walras first formulated the state of the economic system at any point of time as the solution of a system of simultaneous equations representing t… - Kenneth Arrow

I don't know which way human psychology will go wrong. We have a world in which there is uncertainty. There are new technologies. And one of the problems is that we do things today with a thought to the future. Any purchase is one for the future. If you buy a refrigerator you are making a commitment to the future, so that you have food to eat for the next ten years. That's a simple theory, one of many simple theories -- theories that people agree on and that don't, in a fundamental way, change. But every once in a while there is unemployment, and wages will drop, and there will be several different interpretations.

In fact, is is not a mere empirical accident that not all the contingent markets needed for efficiency exist but a necessary fact with deep implications for the workings and structure of economic institutions. Roughly speaking, information about particular events, even after they have occurred, is not spread evenly throughout the population. Two people cannot enter into a contract contingent on the occurrence of a certain event or state if only one of them in fact will know that the event has occurred. A particular example of this is sometimes known as “moral hazard” in the insurance and economic literature. The very existence of insurance will change individual behavior in the direction of less care in avoiding risks.

This is by no means a "formal" matter. Clearly, the intuition behind the continuity requirement is a small step in the direction of utilitarian ethics; even the worst-off member of the society might be made to suffer if there is enough benefit to others. The assumption of diminishing marginal utility implies with regard to usual policy alternatives that there are better ways of improving the lot of better-off members than by hurting the worst-off.
But there is one striking case, of great practical importance, where our intuition is in favor of utilitarianism is some form as against any minimax rule. I refer to allocation over time. Typically, we expect future generations to be better off than we are. Should we save for them either directly or in the form of public investments? A maximin rule would surely say no. But if investment is productive, so that, in terms of goods, the next generation gains more than we lose, we usually feel that some investment is worthwhile even though the recipients will be better off than we are.