Knowledge, Truth, Belief, and Justification

Knowledge Principles

  • Knowledge involves three necessary components: belief, truth, and justification.

  • Justification typically involves having good reasons, evidence, or experiences that support a belief.

  • This course assumes a quest to gain knowledge through these components.

Truth (Metaphysical Theories)

  • Realism: There is truth and objective facts in a domain.

  • Nihilism: There are no facts or truths in a domain.

  • Relativism: Truth exists but is subjective, not objective.

  • Skepticism: Denies that we can have knowledge, not necessarily that truth exists.

  • Arguments against knowledge often involve scenarios like dreaming, evil scientists, or simulations.

  • Skeptic's argument: (1) If you’re not sure you’re not dreaming/simulated, then most of your beliefs are unjustified. (2) You’re not sure you’re not dreaming/simulated. (3) Therefore, most of your beliefs are unjustified.(1) \text{ If you’re not sure you’re not dreaming/simulated, then most of your beliefs are unjustified.} \ (2) \text{ You’re not sure you’re not dreaming/simulated.} \ (3) \text{ Therefore, most of your beliefs are unjustified.}

  • Responses to skepticism:

    • Skeptic's standards for knowledge are too high.

    • Universal skepticism is self-defeating (contradiction: "all beliefs are unjustified" AND "skepticism is justified").

  • Default Position: Realism is adopted as a working hypothesis due to issues with Nihilism, Relativism, and Skepticism (all are self-defeating if universal). For instance, if Nihilism states "there are no truths," that statement itself would have to be true, creating a contradiction. Similarly, if Relativism claims "all truth is subjective," then this claim itself is only subjectively true, undermining its universal application.

Models of Truth

  • Coherence Model: A statement is true if it fits consistently with a body of other justified beliefs.

    • Drawbacks:

    • Not sufficient for truth (e.g., a coherent dream world might feel real, but the beliefs within it are not objectively true outside the dream).

    • Not necessary for truth (e.g., a new scientific discovery, initially conflicting with an existing body of coherent beliefs, can still be true).

  • Correspondence Model: A statement is true if it corresponds to the way things really are (to facts/reality).

  • One Truth Value Principle (OTV): Every proposition, at a given time, is either true or false; it cannot be both or neither.

  • Challenges to the Correspondence Model:

    • Statements about morality, counterfactuals, or the future don't easily map to objective facts or reality in a straightforward empirical way. For example, how does the statement 'murder is wrong' correspond to an objective fact in the world? Or 'If I had studied harder, I would have passed' for counterfactuals. Similarly, statements about the future like 'it will rain tomorrow' pose challenges as the 'fact' they refer to hasn't occurred yet.