The problem, I think, is highlighted, by the IEP's discussion of false dilemma. The example given is:
I want to go to Scotland from London. I overheard McTaggart say there are two roads to Scotland from London: the high road and the low road. I expect the high road would be too risky because it's through the hills and that means dangerous curves. But it's raining now, so both roads are probably slippery. I don't like either choice, but I guess I should take the low road and be safer.
Most people, I think would regard this as perfectly rational. But it's an example in an article on fallacies, so it must be made to fit a fallacy:
This would be fine reasoning is you were limited to only two roads, but you've falsely gotten yourself into a dilemma with such reasoning. There are many other ways to get to Scotland. Don't limit yourself to these two choices. You can take other roads, or go by boat or train or airplane.
This line of thought is utterly baffling. What in the original scenario even remotely suggests that any of these alternatives are real options under the circumstances? The whole structure of discussion here is:
'There are two roads to Scotland, and both have risks, but one seems especially dangerous; so I'll take the safer one.'
'Fallacy! You can also take a boat.'
What kind of analysis of reasoning is that? Not any kind at all; there's no identifiable error in the reasoning, and the ground for calling it a fallacy has nothing to do with the actual reasoning given anyway. But I don't think this is a slip-up; this appears to be just what you usually get in discussions of false dilemma.
Here are the examples ChangingMinds.org gives for the fallacy:
Either you are with me or against me.
We have to spend less on hospitals, otherwise we won't be able to afford education improvements.
These aren't even examples of reasoning! They might possibly be false, but there is nothing about them that's fallacious, because there is nothing about them that is even the right kind of thing for being fallacious. I'm not sure what to make of the more abstract characterization:
Either A or B is true. If A is true, B is therefore false. C is not an option.
The other person is offered a choice where rejecting one item acts as a selection of the other.
A or B; A -> ~B; ~C. Are these supposed to be premises? Is ~C a conclusion or an assumption? Or does the fallacy lie in taking 'A or B' to mean 'A implies ~B' rather than (as it usually would be) '~A implies B'? That would be interesting, but it's the opposite of what the next line says. And indeed the next line just seems to be describing disjunctive syllogism or eliminative argument, which is not any kind of fallacy at all. If you start with 'A or B' and reject one of the the items, you are left with the other. That's not fallacious, that's just logical. The discussion doesn't help any; it says the problem is that we are assuming that there are only two options. But a false assumption is not fallacious reasoning.
Or let's try Logically Fallacious. The examples given are:
You are either with God, or against him.
I thought you were a good person, but you weren’t at church today.
These aren't examples of reasoning, either! It also says, "It is also not a fallacy if other options exist, but you are not offering other options as a possibility." But surely it is always the case that if you put forward only two options and treat them as the only options, you aren't offering other options as a possibility. And this is just how disjunctions work in actual arguments: they are divisions of possibilities.
So how about Nizkor, which is usually pretty careful? Here is the first Nizkor example:
Either 1+1=4 or 1+1=12.
It is not the case that 1+1=4.
So at least this is reasoning. But it's also valid reasoning. The only thing that is wrong with it is that one of the premises is false. And indeed it goes on to say, "In cases in which the two options are, in fact, the only two options, this line of reasoning is not fallacious." But this is just to say that 'the fallacy of false dilemma' is equivalent to 'an instance of an argument with a false disjunction as a premise' -- there's nothing about the line of reasoning that is fallacious at all. The confusion continues with the rest of the examples:
Senator Jill: "We'll have to cut education funding this year."
Senator Bill: "Why?"
Senator Jill: "Well, either we cut the social programs or we live with a huge deficit and we can't live with the deficit."
Bill: "Jill and I both support having prayer in public schools."
Jill: "Hey, I never said that!"
Bill: "You're not an atheist are you Jill?"
"Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for a while."
Senator Jill is reasoning perfectly well -- perhaps her premise is wrong, the reasoning itself is good. In the second, Bill seems only to be making a false assumption. The third is not a kind of reasoning; it's just a disjunctive proposition!
So what about onegoodmove.org? I won't list the examples, because, again, none of them are any kind of reasoning. But the discussion at least fits: the 'fallacy' is described as being a case of giving a limited number of options when really there are more -- or, in other words, it's just a false disjunction.
So, the basic point to be made so far is that having a false premise is not committing a fallacy of reasoning; this seems to be a common error. If we're in colloquial conversation and you want to use 'fallacy' to mean 'false statement' or 'valid but unsound argument', I suppose I can't stop you, but this usage has no business in discussions of logical fallacies.
Enough with the non-starters. Are there any reasonable suggestions for what a false dilemma might be that would make it a kind of error of reasoning?
The Fallacy Files makes the suggestion that it involves treating logical contraries as if they were logical contradictories, which at least starts with the properties of the reasoning. But it is also just practically equivalent to the false assumption accounts, since you can reason with contraries in the same way you would reason with contradictories if you assume the premise that any other options can be ruled out in context.
The IEP article, in both its false dilemma and its black-or-white entries at several points talks about unfair presentation of choices (something similar is occasionally found elsewhere, I suspect due to the influence of this article). I confess that this did not occur to me at all. I've argued before that a better division of fallacies than is usually given is to divide them into the following groups:
(1) structural error (these are usually called formal fallacies)
(2) means-end error (the argument fails to achieve a needed further end; for instance, petitio principii or ignoratio elenchi)
(3) end error (the argument is used for an inappropriate further end; for instance, poisoning the well)
'False dilemma' is a label that sounds like it should be either a structural error or a means-end error of reasoning. But the notion of 'unfairness' is an ethical criticism, which would put it securely in (3): the problem with false dilemma, the thing that makes it a fallacy, is that you are not reasoning in a way that is ethically appropriate. The Scotland example is not a very good example of this at all -- there doesn't seem to be any way in which it is being unfair, and, in fact, the response to it seems a better candidate for unfair reasoning -- but the idea itself, that false dilemma is a violation of fairness in reasoning, is entirely coherent and is a truly interesting suggestion.
I don't know quite what to make of this -- as I said, I found it unexpected. But in favor of it is the fact that it would explain why the examples all fail so miserably -- end-error fallacies are the most context-dependent kind of fallacies. To criticize reasoning for unfairness, if you are being reasonable, you must look at the context in order to determine what would be fair in that particular case. So you can't just give the argument itself -- no fallacy will be visible, because you will not have given anyone the right kind of information to determine whether the argument is being used unfairly.