Why Domain Knowledge Matters More Than We Think
Critical thinking has become ubiquitous in educational discourse. It appears in policy documents, school improvement plans, and job descriptions with the confidence of settled truth. But scratch beneath the surface and the certainty crumbles: what exactly do we mean by critical thinking? Is it a discrete skill that can be taught on Tuesday afternoons? A general capacity that transfers seamlessly from analysing Shakespeare to evaluating scientific claims? Or something else entirely? The term gets thrown around with such frequency that we’ve stopped asking what we actually mean—and whether what we’re promising is even possible.
Tom Sherrington’s The Learning Rainforest fundamentally changed how I thought about teaching, and Dan Willingham’s Why Don’t Students Like School? did much the same. So when Tom and Emma (Co-hosts on one of my favourite educational podcasts) sits down with Dan on the Mind the Gap podcast, it’s not casual listening—it’s leaning in, ready to have my thinking challenged again. This conversation didn’t disappoint.
One of the biggest claims I hear is that critical thinking is a transferable skill… however, cognitive psychologist Dan Willingham would disagree.
The Latin Fallacy
Dan traced this misconception back over a century to when Latin was commonly taught in American schools. The justification wasn’t primarily about learning a language—it was that Latin’s logical, orderly grammar would train students to think logically in all areas. Learn to parse Latin sentences, the argument went, and you’d become a more logical thinker everywhere.
Edward Thorndike tested this claim by comparing students who studied Latin with comparable students who studied French. After their language courses, did the Latin students get better grades in other subjects? No. The supposed transfer of logical thinking simply didn’t happen. The skills stayed tied to the context in which they were learned.
The Problem with “General” Critical Thinking Tests
Modern critical thinking assessments face a fundamental problem: they need content to test thinking, but they want to avoid privileging students who happen to know chemistry or economics. So they create problems they believe are “everyday” or “content-neutral.”
Dan described a typical example from an English A-level critical thinking exam: if you wanted to sell ice cream on a beach where another vendor already operates, should you set up next to them or further down the beach? The test designers presumably thought this was a universal reasoning problem. But as he noted, students who’d studied economics or business would immediately recognise the principle at work, why shops of the same type cluster together.
The same pattern appears in reading comprehension tests. Test designers know background knowledge affects comprehension, so they write passages about “ants and mountains and stuff that they figure most people know about.” But research shows that people with broader general knowledge, which correlates strongly with family income and learning opportunities, score better on these supposedly neutral tests.
What This Means for Teaching
Dan’s alternative is straightforward but requires a shift in thinking: stop trying to teach or test critical thinking as a free-floating skill. Instead, embed it in curriculum content.
His example: “The kids studied whales this year and the kids studied inductive reasoning. We’re going to test inductive reasoning in the context of knowledge about whales.”
This approach offers multiple advantages. Teachers know exactly what content and thinking skills the assessment values. Students aren’t disadvantaged by gaps in “general” knowledge that test designers assumed everyone possessed. And critically, it acknowledges reality: thinking well requires thinking about something, and thinking about something requires knowledge.
The Ice Cream Vendor Problem
The ice cream vendor question perfectly illustrates why “content-free” critical thinking is largely a fiction. Someone might reason through it using pure logic, but someone who understands market dynamics, competitive positioning, and consumer behavior has a massive advantage. Is that an unfair advantage? Not really—it’s just knowledge doing what knowledge does: making certain types of thinking possible.
As Dan explained, manipulatives and concrete examples work in teaching when they help students bridge from something they already understand to something new. The same principle applies to critical thinking. You can’t think critically in a void. You need something familiar to reason from.
The Uncomfortable Truth
What Dan leaves us with is somewhat uncomfortable: there’s no shortcut to critical thinking through generic skills training. Students become better thinkers by knowing more things, deeply, across domains.
The implication for schools is clear but challenging: instead of discrete “critical thinking” lessons divorced from content, we need rigorous subject teaching that deliberately develops reasoning within each domain. A student who thinks critically in history does so because they know history well enough to recognize patterns, spot contradictions, evaluate sources, and construct arguments—not because they completed a module on “critical thinking skills.”
The good news? This validates what many teachers already know works. The hard news? There’s no magic curriculum or quick fix. Deep knowledge takes time, and critical thinking comes as its reward.
If you would like to listen to the Whole Podcast on Mind the Gap you can do so here. If you would like to watch it on You Tube then that the link for that is here.
