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
• 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
• 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
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
The minimum requirement
– Internal consistency – free of contradictions
– External consistency – consistent with the
data it is supposed to explain
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
• 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
• 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.
• The simpler theory is the better theory.
• Copernican hypothesis vs. the Ptolemaic
• The theory that is most consistent with
previously held beliefs is the better theory.
• This is the problem with most conspiracy
Evaluating theories: The TEST
• State the Theory and check for
• Assess the Evidence for the theory
• Scrutinize alternative theories
• Test the theories with the criteria of