You Can’t Think Critically About What You Don’t Know

At the beginning of the internet age, as a student teacher I heard a lot of discussion about how teaching would fundamentally shift in the new information age. Students don’t need to memorize facts because looking up what they need to know is now so easy. Instead, teachers should focus on expanding students’ ability to think critically, analyze evidence, solve problems, and construct arguments.

As a former social studies teacher, I have always found that distinction problematic.
Students certainly need to learn how to think. But they need something to think with.
If I put a collection of primary sources in front of students and ask them to construct an argument about the causes of the Civil War, they cannot do much with those sources if they know almost nothing about the institution of slavery, sectionalism, westward expansion, the political compromises of the nineteenth century, or the events that led to secession.

They may be able to read the words. They may be able to identify a claim. They may even be able to find a quotation that sounds relevant. But without context, they are largely guessing at significance. Critical thinking doesn't replace knowledge. It depends on it.

Science Has the Same Problem

I have been thinking about this increasingly as I look at the shift toward phenomenon-based science instruction. Asking students to investigate phenomena, analyze evidence, develop models, ask questions, and construct explanations, to do science, makes for better science instruction. Science should not be reduced to memorizing vocabulary and reading about concepts from a textbook. But there is a risk of creating the same false choice we created in social studies: facts or thinking. Science students need both.

Ask a group of sixth graders to make sense of a scientific phenomenon involving thermal energy. One student enters the lesson with a fairly robust understanding of matter, temperature, insulation, and energy transfer. Another student has encountered those ideas only superficially. We may give those students exactly the same phenomenon, investigation, and opportunity to reason.

But we have not given them the same starting point. The student with more knowledge has more to connect the new experience to. The student without that foundation is trying to understand the phenomenon, learn unfamiliar vocabulary, determine which information matters, and reason about all of it simultaneously. That is not simply a reading problem. It is a knowledge problem.

The Challenge Falls on the Teacher

This also creates significant implementation challenges for teachers. An adopted science curriculum may provide a carefully designed progression of phenomena, investigations, models, and discussions. But the curriculum cannot know what every student in the class already knows, and that leaves the teacher to identify and fill the knowledge gaps that stand between students and the lesson.

What do students need to know before they begin? Which vocabulary needs to be introduced? Which gaps can be addressed as the lesson unfolds? Which concepts should not be explained in advance because discovering them is part of the investigation?
And how does a teacher provide that support without turning every lesson into a separate remediation exercise?

Those are sophisticated instructional decisions. They are especially difficult when a classroom includes students with very different educational experiences, reading abilities, language backgrounds, and levels of prior science instruction.

The Gaps May Begin Long Before Middle School

This problem is particularly important in science because students do not necessarily receive consistent science instruction in the elementary grades. Elementary teachers have enormous demands on their instructional time. Reading and mathematics understandably receive substantial attention, and many elementary teachers are generalists rather than science specialists. As a result, students may arrive in middle school with very different stores of science knowledge.

By sixth grade, those differences matter. By seventh grade, they compound. By eighth grade, when many states assess science across multiple years of learning, those gaps can become highly visible. Yet the middle-school teacher still has a grade-level curriculum to teach, and students’ ability to succeed with it may depend on filling those earlier gaps. Teachers need to help students catch up without slowing down.

Background Knowledge Is Not the Same as Giving Away the Answer

There is also an important distinction between building background knowledge and undermining inquiry. If students are investigating why a particular phenomenon occurs, we shouldn't necessarily tell them the scientific explanation before they investigate it. But that does not mean we should send them into the investigation knowing nothing. We can give them the prerequisite knowledge that strengthens their participation productively without supplying the conclusion they are supposed to reach.

A student investigating plate movement needs some understanding of Earth's structure.
A student studying ecosystems needs a basic understanding of organisms, habitats, and energy. A student studying chemical reactions needs prior knowledge about atoms, elements, and molecules. That isn't replacing sensemaking. it is making sensemaking possible.

A Better Question

Rather than asking whether students should learn facts or learn to think critically, perhaps we should ask: "What knowledge do students need to think deeply about this problem?" That question changes the instructional conversation. It acknowledges that knowledge and inquiry are not opposing approaches. Knowledge makes inquiry richer. Vocabulary makes reasoning more precise. Background knowledge gives students something to connect new information to. And the more students know, the better prepared they are to ask worthwhile questions, recognize important evidence, and construct meaningful explanations.

Helping Teachers Build the Knowledge Floor

This is one of the problems we are exploring with ClassMate. World Book has spent generations creating clear, trustworthy explanations of the world. The opportunity now is to think about how to help teachers establish the knowledge students need before and during grade-level learning.

One response is to build a short knowledge-preparation experience before students enter the most demanding parts of a unit. The goal is not to replace a district's science curriculum or the investigations at the heart of phenomenon-based learning. It’s to make that curriculum easier for teachers to implement and more meaningful for students to access.

Because asking students to think scientifically is critically important. But when we ask them to think deeply about science, we also need to empower them with the knowledge to make that possible.