While the advisory against using a dictionary to resolve such arguments are true, a lot of arguments stem from confusion or disagreement over the meaning of words. Based on the work I’ve done in philosophy, this type of disagreement probably covers 50% of philosophical debates, with about 2% of the participants in such debates admitting that that is what they disagree about.
For example, “Most atheists believe in the divinity of Christ” could be resolved easily without recourse to the empirical world. If I believe that it is possible for someone to be an atheist and believe in the divinity of Christ, then I am using atheist to mean something very different from its actual meaning.
As you wrote earlier, using words invokes connotations regardless of whether a newly assigned definition merits the same connotations. Some on the far left have defined “racism” to mean “is White and lives in the USA.” Appealing to a dictionary is useful in an argument with such a person because it prevents them from using a very charged word inappropriately. Similar tricks occur with “fascism,” “freedom,” “democracy,” and many other such words.
Basically, a dictionary doesn’t decide if an empirical cluster has a certain property, but it does ensure that the word you are using matches the empirical cluster you are referring to. It is irrational to try to prove an empirical fact with a definition. It is not at all irrational if there is any disagreement over what group is picked out by the word, or whether the group picked out by the word must or must not have a certain property, or else the word would not pick them out. More disagreements center on poorly understood definitions than most people would like to admit.
On a related note, this recent series on definitions is quite brilliantly written, Eliezer, even more so than usual.
This dilemma seems like it can be reduced to:
If you take both boxes, you will get $1000
If you only take box B, you will get $1M Which is a rather easy decision.
There’s a seemingly-impossible but vital premise, namely, that your action was already known before you acted. Even if this is completely impossible, it’s a premise, so there’s no point arguing it.
Another way of thinking of it is that, when someone says, “The boxes are already there, so your decision cannot affect what’s in them,” he is wrong. It has been assumed that your decision does affect what’s in them, so the fact that you cannot imagine how that is possible is wholly irrelevant.
In short, I don’t understand how this is controversial when the decider has all the information that was provided.