The fact that truth is prefereble to falsehood during a debate is all that matters, because when your taling about ethics you are talking about what is justified not what can phisicly be done. Justification only takes place in a debate (by definition).
That's quite a good point. Even internally to someone's head, it comes out in the context of a debate.
Argumentation Ethics, baby... Staying in context.
The problem that in UPB it wasn't explicit enough and from there also rise the mistakes there.
but isn't the universality of preferring truth independent of context? The person who debates the UPB claim is defending the *truth* of the falsehood he believes at that moment (truth is not preferable). And it could be said that all actions require a justification prior to choice (causality), be it rational or irrational, spoken or not... In other words, the universality of preferring truth comes from the fact that truth is universal, even inside the irrational mind.
This is, however, not the case for the action axiom, since the concept of purpose is very different from that of truth. There is no logical deduction of universality there for sure.
By the way, what happened last night with this question? I couldn't listen to the show... What did Stef say?