Taxonomies of the unknown

A compilation with references of some classifications, systematics and other orders of what is not known.


The Map of Ignorance (Kerwin, 1983-)

Domains of Ignorance

By Ann Kerwin and Marlys Witte (Q-cubed Programs: What Is Ignorance?). According to Ann Kerwin the Map of Ignorance was developed by her circa 1983. It has later been presented in 1985 and 1986 together with Marlys Witte.

This little map has traveled the globe. On its clones have scribbled Nobel Laureates, U.N. delegates, educators, physicians, artists, students, politicians, inventors, scientists, poets and ponderers from many walks of life. It's just a prop, a cosmic swerve, a silly prompt for exploration and celebration of the fertile home territory of learning. (Ann Kerwin)


Ann Kerwin: Homepage, CV

Ann Kerwin: None Too Solid. Medical Ignorance. Knowledge: Creation, Diffusion, Utilization 15 (December 1993) 2: 166–185.

Abstract: Our ignorance encompasses, at least, all the things we know we do not know (known unknowns); all the things we do not know we do not know (unknown unknowns); all the things we think we know but do not (error); all the things we do not know we know (tacit knowing); all taboos (forbidden knowledge); and all denial (things to painful to know, so we suppress them). Medical ignorance seems especially threatening to many of us. If, however, we are to cope with our vast ignorance of the human body, its powers and processes, we must learn to acknowledge our nescience and optimize it. To do so, we need to rethink the nature and interrelations between knowledge and ignorance. We need to expand our capacities for self-learning and refine abilities to map our complex experience.

Ann Kerwin: On no other planet. 2 essays, 47 pages.


Taxonomy of ignorance (Smithson, 1989)

We are all ignorant in a variety of ways, to various degrees, with respect to specific issues, problems and questions. In fact, it is the increasing awareness of our ignorance of what there remains to know that is most special about the learning process. A taxonomy of ignorance provided by Smithson (1989:9; and 1993:135) suggests a variety of forms:

  1. All the things of which people are aware they do not know (the most recognised form of ignorance);
  2. All the things people think they know but do not (ignorance based on error);
  3. All the things of which people are not aware that, in fact, they do know (intuition);
  4. All the things people are not supposed to know but could find helpful (taboo);
  5. All the things too painful to know (psychological suppression of memory); and
  6. All the things, of which people are not aware that they do not know (ignorance-squared).

— Thompson H: Ignorance and Ideological Hegemony. A Critique of Neoclassical Economics. Journal of Interdisciplinary Economics 8 (1997) 4: 291–305.

References as provided by Thompson:

Photocopy (excerpt) "Smithson's taxonomy of ignorance" (image on the right) is taken from Jousselme AL et al.: Uncertainty in a situation analysis perspective. ISIF 2003.

Bammer G, Smithson M: Understanding Uncertainty. Integration Insights (May 2008) 7: 1-7.

Further reading

Smithson M: Ignorance and Science: Dilemmas, Perspectives, and Prospects. Knowledge: Creation, Diffusion, Utilization 15 (December 1993) 2: 133–56 .

Abstract: Discusses scientific ignorance and uncertainty. Highlights include approaching knowledgeable ignorance, including a taxonomy of ignorance and uncertainty frameworks and measures; social constructivism, subjectivity, and scientific realism; strategies for working with scientific ignorance; and frameworks for ignorance representation.


Levels of ignorance (Holtzman, 1989; Denby, Gammack, 1999)

Ignorance Level Description Knowledge Required
Combinatorial Computational task too difficult, e.g. problem with 1040 variables. Mathematics model available; use of supercomputers.
Watsonian Cannot make the connection from all the clues; solution method incomplete. Method for determining the important facts from the unimportant ones, and drawing the right conclusion.
Gordian King Gordius tied a knot for the future king of Asia to untie. Alexander the Great was able to “untie it” by cutting the knot with his sword, thus solving the problem in an unusual way. Lateral thinking; are there “rules” to be broken?
Ptolemaic Attributed to the Greek mathematician and astronomer, Ptolemy, whose model of the universe centered around a stationary earth. Evidence and observation of reality.
Magical “No one knows how it works, but everyone knows that it works”, e.g. the use of Aspirin and other similar drugs. Trial and error.
Dark No model is available but one is aware of the issues, e.g. “What is Life?”, “Consciousness”, etc. Future of Science
Fundamental Unaware of issue. (Ignorance is bliss!)

Ignorance can be construed as the state of there being corresponding knowledge 'out there' inaccessible to the decision maker. Holtzman (1989) identified several levels of ignorance by describing the equivalent knowledge paradigm within which it occurs. Table 1. [shown here] presents an expanded version of the Taxonomy.

— Denby E, Gammack J: Modelling Ignorance Levels in Knowledge-Based Decision Support. Proceedings of the 2nd Western Australian Workshop on Information Systems Research 1999.

Denby & Gammack are referring to


5 orders of ignorance (Armour, 2000)

  0th Order Ignorance — Lack of Ignorance
  1st Order Ignorance — Lack of Knowledge
  2nd Order Ignorance — Lack of Awareness
  3rd Order Ignorance — Lack of Process
  4th Order Ignorance — Meta Ignorance.


Sources of surprise (Lawn, 2001)

  1. Surprising events where the range of all possible outcomes is known a priori (risk and uncertainty)
    1. Probabilities all known — Risk (predictable in principle)
    2. Probabilities not all known — Uncertainty (predictable in broad terms)
  2. Surprising events where the range of all possible outcomes are not known (ignorance)
    1. Open ignorance: "In the event that a society is aware of its ignorance, that is, it chooses not to believe something until proven true, it is in a state of open ignorance. Only in a state of open ignorance is it possible for a society to fully experience novel and surprising events."
      1. Reducible ignorance "can be partially or fully overcome through learning and the application of the scientific method".
      2. Irreducible ignorance (Novelty and Complexity): "never amenable to scientific tools of learning and research. In this instance, outcomes have the potential to emerge that one never could envisage a priori."
    2. Closed ignorance: "When a society deliberately overlooks its ignorance, that is, it chooses to believe what it has yet to prove to be true, it is in a state of closed ignorance. Closed ignorance, particularly if it exists in the form of assumed omniscience (e.g., believing the macroeconomic subsystem can grow forever), is a significant barrier to humankind positively influencing the evolutionary pathway of the global system."


Ignorance of the irreducible variety exists because of two ever present factors. The first is owing to complexity. Here, an outcome is unexpected because the complexity surrounding underlying processes of certain dynamic systems precludes the possibility of gaining a comprehensive understanding of them. In the second instance, irreducible ignorance stems from the emergence of novelty. Novelty arises because systemic parameters are forever evolving. This leads to adaptive and somatic change in the short and medium terms, and genotypic change (bifurcation) in the long term. Novelty results in irreducible ignorance because, in not knowing the initial boundary conditions governing the global system's evolutionary pathway, one cannot predict the future pathway of the global system in principle or in broad terms.

— Philip A. Lawn: Toward Sustainable Development. An Ecological Economics Approach. CRC Press, 2001.

According to Lawn, figure "Sources of surprise and a taxonomy of ignorance" (see image on the right) is adapted from Faber et al., 1992, page 84. Reference as provided by Lawn:


Varieties of ignorance (Berry, 2005)

Dave Pollard presented a summary of Wendell Berry's "varieties of ignorance":

— Dave Pollard: The Way of Ignorance. Published on-line, 2006-11-20.

Dave referred to



LeoNora M. Cohen 1996

Cohen LM: Mapping the domains of ignorance and knowledge in gifted education. Roeper Review 18 (1996) 3: 183–189. From its abstract: “(…) a process model is suggested borrowed from the field of medicine. Based on Kerwin’s Map of Ignorance, a Map of Knowledge and Ignorance is offered with several suggestions for its use.”

Anthony Judge 2013

Judge A: University of Ignorance. Engaging with nothing, the unknown, the incomprehensible, and the unsaid. Draft, published online 2013-02-13.


Further reading

Kruger, Dunning 1999

Kruger J, Dunning D: Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments. Journal of Personality and Social Psychology 77 (1999) 6: 1121–1134.

Abstract: People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.


These notes were researched and compiled mostly in August 2008; last minor update 2022-04-16.

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