The Problem of Specifying What Students Should Know
Educational systems routinely specify intended learning outcomes — the knowledge, skills, and dispositions that students should acquire as a result of their education. But the apparent clarity of this specification is often illusory. The term "knowledge" is used promiscuously to cover phenomena that are logically distinct: propositional knowledge of facts and theories, procedural knowledge of how to perform tasks, acquaintance knowledge of particular persons and places, and conative knowledge of how to exercise rational choice. Treating these as instances of a single thing called "knowledge" obscures the different conditions under which they are acquired, the different methods by which they are assessed, and the different values they serve.
James E. Christensen's taxonomy of knowing addresses this problem by distinguishing four fundamental kinds of knowing and four levels of expertise within each kind. The result is a matrix that provides a more rigorous and more useful basis for specifying intended learning outcomes than any of the dominant frameworks in educational psychology — including Bloom's taxonomy, which conflates logical and psychological categories in ways that generate persistent confusion.
Four Kinds of Knowing
Knowing-that-one is acquaintance knowledge — performance in relation to unique or singular states of affairs. To know-that-one is to have direct acquaintance with a particular: a person, a place, an event, a work of art. This kind of knowing is not reducible to knowing propositional facts about the particular, though it may involve such facts. I may know many facts about Paris without knowing Paris in the sense of acquaintance; and I may know Paris in the sense of acquaintance without being able to articulate all the facts that constitute that acquaintance.
Knowing-that is propositional knowledge — performance in relation to categories, theories, and general statements. To know-that is to know that something is the case: that water is H₂O, that the Battle of Hastings occurred in 1066, that reinforcement increases the probability of a behavior's recurrence. This is the kind of knowing that is most naturally expressed in declarative sentences and most readily assessed by recall and recognition tests.
Knowing-how is procedural knowledge — the ability to use procedures to achieve results. To know-how is to be able to do something: to ride a bicycle, to solve a quadratic equation, to conduct a semi-structured interview. Ryle's famous distinction between knowing-that and knowing-how points to a genuine logical difference: one can know how to do something without being able to articulate the rules that govern the procedure, and one can articulate the rules without being able to perform the procedure.
Knowing-to is conative knowledge — the ability to exercise rational choice based on normative principles. To know-to is to be disposed to act in accordance with relevant norms when the occasion arises: to know-to be honest, to know-to seek evidence before forming beliefs, to know-to consider the interests of others in making decisions. This kind of knowing bridges the cognitive and motivational dimensions of learning in ways that purely propositional or procedural accounts of knowledge cannot capture.
Four Levels of Expertise
Within each kind of knowing, Christensen distinguishes four levels that track the development of expertise from novice to innovator:
Preconventional knowing is the knowing of the beginner — unstructured, inconsistent, dependent on external guidance, and without mastery of the basic conventions of the domain. The preconventional learner has been exposed to the relevant content but has not yet internalized the patterns that define competent performance.
Conventional intermediate knowing is the knowing of the learner who has acquired the basic conventions of the domain — who can perform with appropriate guidance and support, who recognizes correct and incorrect performances, and who is developing the habits and routines that support more independent functioning.
Conventional expert knowing is the knowing of the mature practitioner — habitual, efficient, confident, and largely automatic. The conventional expert has thoroughly internalized the conventions of the domain and can apply them flexibly across the range of typical cases without deliberate effort.
Postconventional knowing is the knowing of the innovator — the practitioner who has so thoroughly mastered the conventions of the domain that they can transcend them, creating new conventions, solving novel problems, and extending the boundaries of the domain itself. This is the level of knowing associated with genuine intellectual creativity and with what Christensen calls "neo-search": the generation of new knowledge rather than the application of existing knowledge.
Implications for Curriculum and Assessment
The practical implications of this taxonomy are considerable. Curriculum designers who use it are forced to specify not merely what students should know but what kind of knowing they are aiming for and at what level. A learning outcome that specifies "students will know the causes of World War I" is underspecified: does it call for knowing-that (propositional knowledge of historical facts), knowing-how (the ability to construct a causal argument from historical evidence), or knowing-to (the disposition to seek multiple causal explanations before forming a historical judgment)? And at what level of expertise? These are not pedantic questions — they have direct implications for instructional method and assessment design.