It is this thinking which I think gives rise to the greatest tragedies of history, this sense of commitment to a past purpose which reinforces the or… - Kenneth Arrow

Multiple discoveries are in fact very common in science and for much the same reason. Developments in related fields with different motivation help one to understand a difficult problem better. Since these developments are public knowledge, many scholars can take advantage of them. It is pleasant to the ego to be first or among the first with a new discovery. However, in this case at least, the evidence is clear that the development of general equilibrium theory would have gone on quite as it did without me.

There is little warrant for the belief that we know the laws of history well enough to make projections of any great reliability. Most of the turning points of history, great and small, were surprises to both their participants and the analysts of the day, whatever their doctrine.

The case for equality may be made on other than utilitarian grounds; thus J. Rawls has, argued for maximizing the minimum utility, rather than the sum of utilities, as an ethical criterion, and this criterion would tend toward output equality and therefore strong input progressivity.