The Myth of the Framework is an essay Popper wrote that was published in the book of the same title. The point of the essay is that relativists tend to set excessively high standards for making progress. I would add that this is not just a problem for relativists: it is is a very widespread and extremely damaging obstacle to intellectual and moral progress. The idea that some people are not worth debating is particularly damaging.
First I’ll briefly describe the content of the essay. Everybody should read it. I’d recommend reading it before you see my summary. Relativists tend to say that people need to agree on a lot of stuff to make progress. If people don’t agree with one another a lot they will just talk past one another. If two people are close to agreeing, they may find it pleasant to talk to one another. They might even come to agree so much on the matter they are debating that they can’t find any difference of opinion. However, most of the time that doesn’t happen. People have a discussion and leave the discussion without convincing one another. However, when a good discussion winds up the participants are left wanting to re-examine their ideas and at a minimum they will want to find better ways to put their ideas across. This is progress. The people in that debate will have found that some tactics don’t work for persuading people. Sometimes a person might feel a bit bad about something he said in a debate and take steps avoid it in future. Sometimes a person will get angry and write something he shouldn’t have written and then he should look at why he got angry and try to avoid it in the future. or he might have made an argument from authority: you haven’t done X and I have, so you can’t improve my knowledge of X. This is such a bad argument: it’s authoritarian and inductivist. Popper also points out that requiring people to agree on terminology before starting a discussion is a bad idea. Languages contain knowledge about how the world works. For example, our current number system is better than the Roman number system because multiplication is a lot easier and so on. So if you require people to agree on terminology, you’re requiring that they agree on substantive matters where they might have a real disagreement.
Now some commentary: many people have very high standards for what counts as agreement when trying to decide how to cooperate with somebody. Suppose, for whatever reason, that Bill wants to cooperate with Bob on watching a film together. At first, Bob wants to go out to the cinema, but Bill is depressed and doesn’t want to go outside. They might decide that it’s better to stay in and watch a DVD. They might have different reasons for wanting to stay in. For example, Bob might not have seen the DVD film, but he’s heard it’s really good and he wants to watch it, and besides, cinema popcorn is ridiculously expensive. Bob doesn’t have to agree that being depressed is a good reason not to go outside. All that has to happen for them to cooperate on watching the film is that they agree that watching the DVD is better than going to the cinema. If you have higher standards for solving a problem than that, many problems will begin to look far more intractable than they are.
Now of course, there are occasions on which you might want to do X with somebody but disagree with why they want to do X. You might want to have a debate about the reason for X later, but you don’t have to have that debate to do X, or to agree that X is right. One context in which this arises is the following: suppose you’re having a debate with somebody and he pulls some really crappy debating tactic, like an ad hominem argument. Now you should say ‘that ad hominem argument is bad’ and explain why. You shouldn’t refuse to debate with somebody jut because they use ad hominem, for all you know nobody has bothered to explain why it’s bad.
There are some people who see the point of argument solely as winning points and are willing to play dirty to do it. You might decide not to debate with a person like that because you don’t know how to get them to debate honestly. But that’s not because progress is impossible in that instance, it’s just because you don’t know how to make progress in that instance. If you could change that person’s mind about the point of debating and get him to argue honestly that would be worth doing. So it’s not the case that the person isn’t worth debating, it’s just that you don’t want to do it because you don’t know how to get something good out of the debate.