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Justified True Belief Venn Diagram

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About This MicroSim

This interactive MicroSim helps students explore the concept. It supports the learning objectives in Chapter: Theories of Truth and Knowledge.

How to Use

Use the interactive controls below the drawing area to explore the visualization. Hover over elements for additional information and click to see detailed descriptions.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

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<iframe src="https://dmccreary.github.io/theory-of-knowledge/sims/jtb-venn-diagram/main.html"
        height="450px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Grade Level

9-12 (High School / IB TOK)

Duration

15-20 minutes

Prerequisites

  • Basic understanding of what a "belief" is in philosophical terms
  • Familiarity with the distinction between truth and opinion
  • Introductory exposure to the question "What is knowledge?"

Learning Objectives

  • Classify beliefs into the correct regions of the JTB Venn diagram based on whether they are justified, true, and/or believed
  • Explain how the intersection of all three conditions (justified, true, believed) constitutes knowledge under the classical definition

Activities

  1. Exploration (5 min): Click on each region of the three-circle Venn diagram to read its description. Identify what each region represents: beliefs that are true but unjustified, justified beliefs that are false, and so on. Pay special attention to the center where all three circles overlap — this is the classical definition of knowledge.
  2. Guided Practice (10 min): If the sim has a quiz mode, drag example beliefs into the correct Venn diagram region. For each placement, justify your choice aloud or in writing. Then consider Gettier cases: can you think of a belief that is justified, true, and believed — yet still seems like it is not genuine knowledge? Discuss the "lucky true belief" problem with a partner.
  3. Assessment (5 min): Given a novel scenario (e.g., "A student guesses the correct answer on a test and can explain why it is correct, but their reasoning is based on a flawed textbook"), determine which JTB region it belongs to and whether it qualifies as knowledge. Write a 2-3 sentence justification.

Assessment

  • Correctly identifies what each region of the Venn diagram represents
  • Accurately places at least three example beliefs into the correct JTB regions
  • Articulates the significance of Gettier cases in challenging the JTB definition of knowledge

Quiz

Test your understanding with this review question.

1. A student believes that Canberra is the capital of Australia because they confused it with a trivia answer about Canada. The belief happens to be true, and they feel confident about it. Under the JTB framework, why might this NOT count as knowledge?

  1. The belief is not true
  2. The student does not actually believe it
  3. The belief lacks adequate justification
  4. The belief is too simple to be considered knowledge
Show Answer

The correct answer is C. Although the belief is true and the student holds it sincerely, the justification is flawed — it is based on a confusion with an unrelated fact. Under the JTB framework, all three conditions must be genuinely met. This is similar to a Gettier case where a true belief is held for the wrong reasons.

Concept Tested: The justification condition in the JTB definition of knowledge

References

  1. Plato. Theaetetus (circa 369 BCE). Translation by M. J. Levett, revised by M. Burnyeat.
  2. Gettier, E. (1963). Is Justified True Belief Knowledge? Analysis, 23(6), 121-123.
  3. Ichikawa, J. J., & Steup, M. (2018). The Analysis of Knowledge. Stanford Encyclopedia of Philosophy.