In my experience, it is a common refrain of "arguments" in our culture that "Well, that's OK...don't worry about it, Reasonable People Can Disagree..." I was once of the opinion that this was a sort of platitude, a sort of polite reflexive utterance of the type "Excuse me." or "Would you mind passing the duck l'orange? Thank you." whose proper application is any moment in a discussion where frustration begins to run high. A sort of escape route to avoid offense, anger, or other calumnitory slanders. I am not so sure anymore.

During the course of my meta-philosophical investigations (how should we DO philosophy anyway?) I casually remarked that, "Well of course reasonable people can't actually disagree..." upon which my interlocutor, without fail, will inform me that they have discovered a point of disagreement. This is not a coincidence. Lo and behold, they disagree with that statement itself! Apparently, this idea of "reasonable disagreement" is perfectly acceptable, expected, perhaps virtually necessary. I have my suspicions that some degree of the indignance to this claim stems from manners rather than reflection, but surely there is more to it than that...

So what do I mean anyway? Of course, individual human beings who are (rightly?) considered "reasonable" appear to "disagree" all the time. Is not my claim empirically falsified countless times daily? Perhaps we would benefit from some refinement:

Iconoclastic Formulation: "Reasonable people cannot disagree."

Slightly More Philosophically Responsible Theoretical Formulation: "Agents of perfect rational faculties, involved in a philosophical discussion, under ideal conditions, with perfect information exchange, for an unlimited amount of time, will eventually reach a point where they have identical assent conditions for any and all constructed conditional arguments."

Admitting that "perfect rationality", "ideal conditions", "perfect information", "unlimited time", etc. are not realizable by us, what I think this recommends to philosophers is the normative claim:

"Intellectually honest individuals involved in a philosophical discussion ought to attempt to understand each position presented (the premises and the rules of deduction or inference in play) and strive for reaching a conditional agreement as to the conclusion(s)."

Should be a lively discussion likely to end in complete controversy.