"Differences that don't make a difference" is a phrase I originally picked up from John Holt in How Children Learn ((How Children Learn #citation)).

In that context, it was about children learning how to speak. The kiddo would hear differences between words - they're not dumb - but had not yet made the connection that the difference between how those words sounded made a difference in what they meant.

Another example on the opposite side of the spectrum is that of understanding what a chair is. We understand that there are many kinds of chairs. All of them are technically chairs, but there are differences in how they look and operate. We know that those are differences that don't make a difference.

One more: A southern American accent is still the english language even though it's very different sounding than Irish english. Some of those differences make a difference, but some don't.

This is a powerful concept during the early phases (The onboarding phase builds confidence in mechanics) of ingesting a new concept. The learner is working hard to generalize the new concepts into digestible chunks. Sometimes it's easy to miss that a dog and chair are two different things, because on the surface they both have four legs. The learner hasn't yet discovered that those are differences that do make a difference.

#toolong