The Logical Point
Teaching does not guarantee learning. This claim may sound obvious, but its logical structure has consequences that are far from obvious — consequences for how teaching quality is defined, how teachers are evaluated, and what accountability for educational outcomes properly requires.
Christensen's argument is analytic: it proceeds by examining the logical form of the concept "teaching." Teaching, he argues, is an intentional activity — an activity that is defined by the intentions of the person performing it and by the nature of the conduct those intentions produce, not by the effects of that conduct on others. A teacher who provides well-designed opportunities for a student's learning of a prescribed range of content is teaching, by definition, regardless of whether the student learns. The student's learning is the intended product of teaching, but it is not constitutive of teaching.
The Contrast with Learning
The contrast between teaching and learning is instructive. Learning, in Christensen's framework, is a process — specifically, the process of acquiring a prescribed range of knowing. Unlike teaching, learning is defined by its product: if no knowing is acquired, no learning has occurred. A student who engages in activities intended to produce learning but acquires no knowing has not learned, by definition. But a teacher who designs and implements those activities in good faith, with appropriate skill and knowledge, has taught — even if the learning does not occur.
This asymmetry has important implications. It means that the failure of learning is not necessarily the failure of teaching. Learning can fail for many reasons that are independent of teaching quality: the student's prior knowledge may be insufficient, the student's motivation or attention may be inadequate, the content may be genuinely difficult, or the assessment may be poorly designed. A system of teacher accountability that holds teachers responsible for learning outcomes without distinguishing these factors will systematically misattribute responsibility.
Implications for Teacher Evaluation
The argument does not imply that learning outcomes are irrelevant to teacher evaluation. It implies that the relationship between teaching quality and learning outcomes is more complex than value-added models of teacher accountability typically assume. A rigorous account of teacher quality must evaluate the quality of the teaching activities themselves — the design and implementation of opportunities for learning — not merely their outcomes, and must distinguish the teacher's contribution to outcomes from the many other factors that shape what students learn.
The Broader Point About Educational Accountability
More broadly, Christensen's argument illustrates the importance of analytic clarity in educational policy. When educational accountability systems are designed without clear concepts of teaching and learning — without attention to the logical distinction between the activity and its product — they tend to produce incentive structures that are both unjust and counterproductive. Getting the concepts right is not a luxury for philosophers; it is a prerequisite for getting the policy right.