Rationality and predictability
合理性与可预测性
There is a close association between rationality and predictability. We expect “rational theories” to yield predictions that match observations. Similarly, we expect “rational individuals” to behave predictably. So “rationality” seems to entail predictability, and “self-regarding choice” seems rational in the sense that it is predictable.
However, it would be wrong to restrict rational behaviour to self-regarding choice. We can rationally hold commitments that go beyond self-goal choice (not just beyond self-regarding choice). Being rational simply entails having defensible reasons for our behaviour. [Note 1] It is not enough for a theory to yield predictions that match observations. We also want to understand why that is the case. Similarly, to make sense of a person’s behaviour is to understand her reasons for so behaving.
That said, it is true that we do not always succeed in achieving the goals and commitments that we have reason to value. It is rational care about the environment, but in practice our behaviour often harms the environment. It is rational to cooperate, but we often do not.
It helps to distinguish “personal choice” from “social choice”. It is true that in matters of personal choice, we often prioritise our own goals over other commitments. But our commitments have more salience when it comes to social choice; we are better able (not just more willing) to meet our commitments when we expect other people to behave in a way that support those commitments.
There is much more scope for reasoned inquiry and/or critique in matters of social choice. First, we are better able to identify and pursue goals and commitments that we collectively have reason to value. Second, we are better able to scrutinise our social institutions and processes to ensure that they help us achieve those goals and commitments. We need not feel pessimistic about the power of reasoning to make a difference in the world.
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Note 1: That is, reasons that stand up to scrutiny from the perspective of others within our own community (“closed impartiality”) and the perspective of an external impartial spectator (“open impartiality”).
理性与可预测性之间有着密切的关系。我们期望“理性的理论”能够得出与观察结果相符的预测。同样，我们也希望“理性个体”的行为有预测性。因此，“理性”看似包含可预测性，而“利己选择”在可预测的意义上似乎是理性的。
然而，将理性行为限制在利己选择上是错误的。我们可以理性的做出超越自我目标选择（而不仅仅是超越利己选择）的承诺。理论仅仅意味着我们的行为有合理的理由。[注1] 理性仅仅得出与观察结果的预测是不够的。我们还想了解为什么会这样发生的理由。同样，要理解一个人的行为，就要理解她这样做给出的原因。
话虽如此，我们并不总是能够成功实现我们有理由重视的目标和承诺。关心环境是理性的，但在实践中，我们行为往往会损害环境。合作是理性的，但我们经常不这样做。
区分“个人选择”与“社会选择”是有帮助的。在个人选择方面，我们确实经常将自己的目标置于其他承诺之上。但在社会选择方面，我们的承诺更为突出；当我么期望其他人的行为方式支持这些承诺时，我们更有能力（而不仅仅是更愿意）履行承诺。
在社会选择方面，进行理性探究和/或批评的空间更大。首先，我们能够更好地确定和追求我们集体有理由重视的目标和承诺。其次，我们能够更好地审查我们的社会机构和流程，以确保它们帮助我们实现这些目标和承诺。我们不必对推理改善世界的力量感到悲观。
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注1: 也就是说，这些理由经得起我们自己社会中其他人的视角（“封闭的无偏无倚”）和外部公正旁观者视角（“开放无偏无倚”）的审查。