Inference to the Best

Explanation

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.

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

• 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.

Inference to the best explanation

• Phenomenon Q

• E provides the best explanation for Q.

• Therefore E is probably true.

• What makes a theory good?

• How should we judge what is the best

explanation?

The minimum requirement

• Consistency

– Internal consistency – free of contradictions

– External consistency – consistent with the

data it is supposed to explain

Criteria of adequacy

• Testability

• Fruitfulness

• Scope

• Simplicity

• Conservatism

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).

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.

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.

Simplicity

• The simpler theory is the better theory.

• Copernican hypothesis vs. the Ptolemaic

theory.

Conservatism

• The theory that is most consistent with

previously held beliefs is the better theory.

• This is the problem with most conspiracy

theories.

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