There are two major reasons to practice tolerance of ideas that differ from, or conflict with, your own:
Epistemic humility: You may be wrong about some things, and even if you’re not wrong, may not fully understand your own position and may not be equipped to defend it against your opponents. Therefore you extend tolerance not only for the sake of your opponents but also for your own intellectual good. (This is a major theme in John Stuart Mill’s On Liberty.)
Political pragmatism: If you’re not powerful enough to silence your enemies, your attempts to do so may bring on a fight you can’t win. Worse, the attempt to silence others may lead to their attempting to silence you — and if they’re sufficiently strong that attempt might just succeed. And then where would you be?
In our current political moment, it is trivially easy to find strong, confident voices that confirm our opinions. And because we do not understand scale, it is easy to believe that everyone who matters, everyone who thinks, everyone who is decent is on our side. Securus judicat orbis terrarum. It is virtually impossible in such a climate to make an appeal to epistemic humility. Therefore tolerance can really only be recommended on the groud of political pragmatism.
But even this is difficult for people for whom political opponents are the Repugnant Cultural Other. As I wrote in yet another essay, “For those who have been formed largely by the mythical core of human culture, disagreement and alternative points of view may well appear to them not as matters for rational adjudication but as defilement from which they must be cleansed.” What is happening on the American left right now, in the wake of the recent election, is a struggle between political pragmatism and the deeply felt need for social hygiene.
Which will win?
UPDATE: This from John Ganz in The Nation is representative of a typical left postmortem of the election:
The Democrats don’t need to program differently — they need to think differently. The main feature tying together the shows that young right-leaning men watch and listen to now is curiosity: They include discussions and debates; their hosts might not be particularly knowledgeable and they are open about it, so they ask what might seem like dumb questions without shame. Even when the discussion veers into pure propaganda, it comes wrapped in the appearance of open inquiry. If liberals want more organic intellectuals like the GOP seems to have, they need to be willing to be more organic — to actually hang and talk, not just hector from above. They need to reject their allergy to “debate bros” and learn how to argue and debate again; indeed, they need to recover the central challenge of politics — to persuade people.
But you can’t persuade people when you feel defiled by their very presence. Thus the choice I have pointed to.
