Ayer on Disagreement

While I sit here working productively after a great day of bike-riding and family reunioning, I still hurt over not deciding to go the the Disagreement conference. To console myself, I'm pondering this Ayer quote I just found while looking for something else.

“One of the main objects of this treatise has been to show that there is nothing in the nature of philosophy to warrant the existence of conflicting philosophical parties or “schools.” For it is only when the available evidence is insufficient to determine the probability of a proposition that a difference of opinion concerning it is justifiable.”

A.J. Ayer, Language, Truth, and Logic. 133.

That strikes me as wierd. It doesn't seem right that an insufficiency of evidnece itself should ever leave indeterminate the probability of a propositon. Rather, we might just not be able to determine how some piece of evidence bears on a proposition. But that's a different matter.

For example A thinks E makes H very probable and B thinks E only makes H soemwhat probable. That's a disagreement, but it has nothing essentially to do with a paucity of evidnece.

Nevertheless, if an instance of the example does come about, then it seems no legitimate disagreement is possible (at least among disclosed, recognized peers), for then they should either suspend judgement or split the difference (depending on the numbers).