 It is a separate question whether pure time preferences are rational. Critics argue that one should want one’s life, as a whole, to go as well as possible, and that counting some parts of life more than others interferes with this goal (Pigou, 1920; Ramsey, 1928b; Rawls 1971). According to this view, it is irrational to prefer a smaller immediate good to a greater future good, because now and later are equally parts of one life. Choosing the smaller good or the greater bad makes one’s life, as a whole, turn out worse: “Rationality requires an impartial concern for all parts of our life. The mere difference of location in time, of something’s being earlier or later, is not a rational ground for having more or less regard for it” (Rawls 1971, 293). Critics of pure temporal preferences often attribute apparent departures from temporal neutrality to a cognitive illusion (which causes people to see future pleasures or pains in some diminished form) or to a weakness of will (which causes people to choose options against their better judgment).