In some ways, the social media age looks like an advert for trying to move the Overton window. Say something extreme in public, bring your allies out of the closet, force your opponents to denounce you (and often overreact in the process), change the terms of the debate, and watch opinion move in your favour.

Perhaps. But another rule to bear in mind—and one with another three hundred years worth of stress-testing—is Newton’s third law: for each reaction, there is an equal and opposite reaction. If you say something extreme enough to move the Overton window, it will frequently provoke others to move in the opposite direction to the one you want. Nigel, meet Jeremy. Bernie, meet Donald.

It happens theologically all the time, at least to me. A Statement on Social Justice and the Gospel comes out, and I scurry away from it as fast as I can. But then Union Seminary respond, and it pushes me back in a conservative direction. I read R. C. Sproul and want to be Arminian, then I read Roger Olson and want to be Calvinist. Nothing convinces me of the need to be inclusive more than reading fundamentalists; nothing convinces me of the need to contend for the gospel more than reading progressives. It happens politically as well: when I read the Guardian I move to the right, and when I read the Telegraph I move to the left. Every reaction produces a counterreaction.

One possible explanation of all this is that I’m a natural contrarian. But I don’t think that’s it, because when I read moderate, centrist, triangulating treatments of controversial subjects—and thankfully there are plenty of those, and I regularly get to share them here—I usually find them compelling and convincing. I think it’s more likely that the very fire and bombast you need to move the Overton window is almost guaranteed, as an unintended consequence, to toughen the resolve of those who disagree with you, even if they express themselves in a more nuanced way than you do. Ask Richard Dawkins.

Staking out extreme positions can certainly shift the terms of the debate. But it can also backfire when it comes to the people you’re trying to persuade. So beware. What you gain on the Overtonian swings, you may well lose on the Newtonian roundabouts.