 To the objection that choice behind the veil of ignorance is psychologically impossible, Rawls says that it is important not to get too caught up in the theoretical fiction of the original position, as if it were some historical event among real people who are being asked to do something impossible. The original position is not supposed to be realistic, but is a “device of representation” (PL 27), or a “thought experiment,” (JF, 83), that is designed to organize our considered convictions of justice and clarify their implications. The parties in it are not real but are “artificial persons” who have a role to play in this thought experiment. They represent an ideal of free and equal reasonable and rational moral persons that Rawls assumes is implicit in our reasoning about justice. The veil of ignorance is a representation of the kinds of reasons and information that are relevant to a decision on principles of justice for the basic structure of a society of free and equal moral persons (TJ 17/16). Many different kinds of reasons and facts are not morally relevant to that kind of decision (e.g., information about people’s race, gender, religious affiliation, wealth, and even, Rawls says more controversially, their conceptions of their good), just as many different kinds of reasons and facts are irrelevant to mathematicians’ ability to work out the formal proof of a theorem. As a mathematician, scientist, or musician exercise their expertise by ignoring their knowledge of particular facts about themselves, presumably we can do so too in reasoning about principles of justice. Rawls says we can “enter the original position at any time simply by reasoning in accordance with the enumerated restrictions on information,” (PL 27) and taking into account general facts about persons, their needs, and social and economic cooperation that are provided to the parties (TJ 120/104, 587/514).