I stuck with Eric Weinstein and Sam Harris for a long time, even though much of the discussion did not excite me. But starting around 2:10 (that is, two hours and ten minutes in), there are three interesting minutes. At one point, Harris says that the far-left fringe influences the mainstream left, whereas the far right fringe does not influence the mainstream right.
I think that is going to be a very controversial statement, so let me suggest how to think about it. What are the examples of actions or positions that people of the mainstream right (and for this purpose, I will allow you to include President Trump in the “mainstream right”) where a reasonable neutral person would agree that (a) your accusation about the mainstream right is correct and (b) that the action or position comes from the fringe right, and if you took away the fringe right it would go away.
For example, if you say that President Trump is anti-semitic, then I would say that this satisfies (b) but not (a)–that is, a reasonable neutral person would not agree that he is anti-semitic. Or if you say that President Trump and others on the mainstream right are nationalistic, I would say that satisfies (a) but not (b). That is you cannot argue that nationalism is a sentiment that would disappear from the right if the fringe would go away.
I think that the strongest case one might make would be with regard to anti-immigrant rhetoric. Clearly, the mainstream right-wing view has shifted since President Reagan’s day, and it has moved in the direction of the right-wing fringe.
Now apply these tests to the left. The NYT’s “1619 project” strikes me as an example of fringe left going mainstream. So does Google’s firing of James Damore. So does the local synagogue where I go dancing on Mondays where “men” has been replaced by “urinals and stalls” and “women” has been replaced by “stalls only.” So do the women’s athletic events that have been won by biological males.
So I think that Sam Harris’ point is basically correct. I think that if I were a Progressive, I would argue that for the left to adopt ideas from its fringe is more of a feature than a bug. Often, it seems that eventually the center (not just the left) does tend to “catch up” with ideas that start on the Progressive fringe. Gay marriage is among many examples that come to mind.
The problem is that there are plenty of fringe ideas on the left that do not deserve to become mainstream. Left-wing anti-semitism comes to mind.
My conclusion is that we do need to apply a filter to left-wing fringe ideas. And we cannot count on left-wing moderates to provide that filter. It could be that the mission of the center-right is to provide a filter for both the fringe ideas on the right and the fringe ideas on the left. But that means that we should not want the center-right to go extinct.