1. Inference to the Best
Explanation

2. Types of explanation
• Teleological – the purpose of something
• Interpretative – the meaning of something
• Procedural – how something works
• Theoretical explanation – theories or
hypotheses explaining why something is
the way it is – including causal
explanations.

3. Theoretical explanation
• Copper burns green because the
excitation of the electrons created by the
heat. The vibration at a particular
frequency results in the emission of green
light (light waves of that frequency).
• Notice how this explanation makes
reference to an overarching theory or
hypothesis

4. • So one might argue that we believe that
the atomic theory is true (even though we
don’t see atoms) because it offers the best
explanation of a wide variety of
phenomena.

5. Inference to the best explanation
• Phenomenon Q
• E provides the best explanation for Q.
• Therefore E is probably true.

6. • What makes a theory good?
• How should we judge what is the best
explanation?

7. The minimum requirement
• Consistency
– Internal consistency – free of contradictions
– External consistency – consistent with the
data it is supposed to explain

8. Criteria of adequacy
• Testability
• Fruitfulness
• Scope
• Simplicity
• Conservatism

9. A theory should be testable
• It needs to be formulated in a way that it is
clear enough what a test would be
• It needs to have empirical consequences
that would show it was false if it were false
(falsifiable).

10. Fruitfulness
• A theory should be useful in leading to
other explorations of the world. It
shouldn’t be a dead end.
• It is a better theory if it predicts previously
unknown phenomena.

11. Scope
• A theory that explains a wider variety of
phenomena has a wider scope.
• Newton’s theory was able to explain
phenomena in the heavens and on earth.

12. Simplicity
• The simpler theory is the better theory.
• Copernican hypothesis vs. the Ptolemaic
theory.

13. Conservatism
• The theory that is most consistent with
previously held beliefs is the better theory.
• This is the problem with most conspiracy
theories.

14. Evaluating theories: The TEST
Formula
• State the Theory and check for
consistency
• Assess the Evidence for the theory
• Scrutinize alternative theories
• Test the theories with the criteria of
adequacy