Many people believe that we should not be friends with others if they have bad enough moral and political beliefs. For instance, they think that we should not befriend KKK members or Nazis. However, not all errors in moral and political belief disqualify people from friendship. If so, then there is some line to be drawn somewhere which indicates when a person's beliefs are bad enough that we should not befriend them. This paper considers many candidate proposals for how and why to draw the line, including that beliefs might be extreme, be held irrationally, dehumanize others, are unreasonable, and more. However, upon inspection, each candidate proposal fails. They either provide the wrong kind of reason to reject people as friends, or they fail to explain what counts as ‘bad enough’ beliefs. There are various arguments in favour of rejecting people from friendship on the basis of their bad beliefs, but these arguments also fail to explain what counts as ‘bad enough’. Thus, this paper concludes there is a genuine puzzle: we should indeed blackball some people from friendship when their beliefs are bad enough, but we do not have even a rough specification of what counts as bad enough.

许多人认为，如果他们的道德和政治信仰足够糟糕，我们就不应该与他人成为朋友。例如，他们认为我们不应该与 KKK 成员或纳粹分子交朋友。然而，并非所有道德和政治信仰上的错误都会使人们失去友谊的资格。如果是这样，那么就可以在某处划出一条线，指示何时一个人的信念足够糟糕以至于我们不应该与他们成为朋友。本文考虑了许多关于如何以及为什么划定界限的候选提议，包括信念可能是极端的、非理性的、非人化的、不合理的，等等。然而，经检查，每个候选提案都失败了。他们要么提供了错误的理由拒绝人们成为朋友，要么他们无法解释什么才算是“够糟糕”的信念。有各种各样的论据支持以不良信念为由拒绝人们建立友谊，但这些论据也无法解释什么才算“够糟糕”。因此，这篇论文得出的结论是，存在一个真正的难题：当某些人的信念足够糟糕时，我们确实应该将他们与他们的友谊拒之门外，但我们甚至没有粗略地说明什么才算足够糟糕。