There are two distinct ways to be politically moderate: on purpose
and by accident. Intentional moderates are trimmers, deliberately
choosing a position mid-way between the extremes of right and left.
Accidental moderates end up in the middle, on average, because they
make up their own minds about each question, and the far right and
far left are roughly equally wrong.
You can distinguish intentional from accidental moderates by the
distribution of their opinions. If the far left opinion on some
matter is 0 and the far right opinion 100, an intentional moderate's
opinion on every question will be near 50. Whereas an accidental
moderate's opinions will be scattered over a broad range, but will,
like those of the intentional moderate, average to about 50.
Intentional moderates are similar to those on the far left and the
far right in that their opinions are, in a sense, not their own.
The defining quality of an ideologue, whether on the left or the
right, is to acquire one's opinions in bulk. You don't get to pick
and choose. Your opinions about taxation can be predicted from your
opinions about same-sex marriage. And although intentional moderates
might seem to be the opposite of ideologues, their beliefs (though
in their case the word "positions" might be more accurate) are also
acquired in bulk. If the median opinion shifts to the right or left,
the intentional moderate must shift with it. Otherwise they stop
Accidental moderates, on the other hand, not only choose their own
answers, but choose their own questions. They may not care at all
about questions that the left and right both think are terribly
important. So you can only even measure the politics of an accidental
moderate from the intersection of the questions they care about and
those the left and right care about, and this can
sometimes be vanishingly small.
It is not merely a manipulative rhetorical trick to say "if you're
not with us, you're against us," but often simply false.
Moderates are sometimes derided as cowards, particularly by
the extreme left. But while it may be accurate to call intentional
moderates cowards, openly being an accidental moderate requires the
most courage of all, because you get attacked from both right and
left, and you don't have the comfort of being an orthodox member
of a large group to sustain you.
Nearly all the most impressive people I know are accidental moderates.
If I knew a lot of professional athletes, or people in the entertainment
business, that might be different. Being on the far left or far
right doesn't affect how fast you run or how well you sing. But
someone who works with ideas has to be independent-minded to do it
Or more precisely, you have to be independent-minded about the ideas
you work with. You could be mindlessly doctrinaire in your politics
and still be a good mathematician. In the 20th century, a lot of
very smart people were Marxists — just no one who was smart about
the subjects Marxism involves. But if the ideas you use in your
work intersect with the politics of your time, you have two choices:
be an accidental moderate, or be mediocre.
 It's possible in theory for one side to be entirely right and
the other to be entirely wrong. Indeed, ideologues must always
believe this is the case. But historically it rarely has been.
 For some reason the far right tend to ignore moderates rather
than despise them as backsliders. I'm not sure why. Perhaps it
means that the far right is less ideological than the far left. Or
perhaps that they are more confident, or more resigned, or simply
more disorganized. I just don't know.
 Having heretical opinions doesn't mean you have to express
them openly. It may be
easier to have them if you don't.
Thanks to Austen Allred, Trevor Blackwell, Patrick Collison, Jessica Livingston,
Amjad Masad, Ryan Petersen, and Harj Taggar for reading drafts of this.