PhilosFX: The Motte and Bailey Fallacy

Monday, June 19, 2023

The Motte and Bailey Fallacy

A medieval Motte and Bailey castle, the namesake for an interesting logical fallacy

Are you interested in logical fallacies? That is to say, do you study common flaws in thinking either to avoid them personally or spot them in sales pitches and other persuasive arguments? In my experience, this has become a critical survival skill.

If you are with me so far, (a) thank you, and (b) have you heard of the Motte and Bailey Fallacy? This particular logical flaw is not as well-known as, say, the Strawman or the Appeal to Authority. And yet, as evidence-based truth-seekers and diligent data skeptics, we must keep our eyes peeled for simple mistakes as well as deliberate attacks.

The motte and bailey fallacy is a rhetorical technique where the proponent is essentially saying two things: one more defensible but less interesting (the motte), and one less defensible but more interesting (the bailey). The concept was invented by Nicholas Shackel and was popularised by Scott Alexander.

In a typical motte and bailey argument, the proponent will establish common ground with the opponent. This safe or neutral space is analogous to the motte. For example, the proponent might ask, "Are you in favor of inclusion?" And the obvious answer is, "Of course!" Who would be opposed to inclusion? Having established the motte, the proponent can now assert that language which is offensive to minorities has the effect of excluding them by making them feel unwelcome. When the opponent counters with a freedom of speech argument, the proponent can claim, falsely, that the opponent is against inclusion. See how it works?

I would welcome your thoughts on this type of fallacy. Please feel free to leave a comment. Have you seen this fallacy before? Can you cite some examples? Will you keep an eye out for it to avoid using it yourself, or being tricked by it?

For your convenience, I have included some references below. Feel free to use those or others of your choosing--there are many just a quick search away.

Thanks for reading. The world needs evidence-based truth-seekers and diligent data skeptics now, more than ever!