Inference to the best explanation,
another inductive inference
Explanations versus arguments:
Arguments give us reasons to think
something is the case. Plausible or
certain premise to uncertain conclusion!
Explanations give us reasons why or how
something is the case. Uncertain premise
to certain/known/factual conclusion/event
TYPES OF EXPLANATIONS
Procedural (how something is done)
Interpretive (why something means
what it does)
Functional (how something works or
Theoretical (why something is the way
it is, why something happened)
The focus of our analysis
Pattern of reasoning: from premises about a
state of affairs (what we know to have
happened) to a conclusion about why this
We often have competing, alternate, comparable
theories or explanations.
We assess which is the best, most plausible,
most likely to be true.
PATTERN OF INFERENCE
More formally, the pattern:
E provides the best explanation for Q
Therefore, E is probably true
Informal: we do it naturally!
When we evaluate whether is does
provide best explanation, we use
PARTS OF EXPLANATION
Explanandum: what is being explained, the
Explanans: the answer or statement that explains
The explanans tries to explain the explanandum by
positing or providing a theory
Sometimes requires imagination to formulate the
Theories expand our knowledge and enable it
Some basic starting points for determining
which of several explanations is best
If you formulate a new or novel one and do not
compare it to others, greater likelihood of it
If other explanations are just as good as yours,
this sheds doubt on yours
If you study and research your explanation,
greater likelihood that it will be plausible
We often observe our surroundings to
determine which of any proposed theories is
i.e., process of determining why your car
Empty fuel tank
PROCESS OF ELIMINATION
Using observation to eliminate theories
Using background knowledge, if any
Notice, we fill in premises to support
why any explanation is best
Used in all academic departments and
many areas of life, courts, etc.
Organizing tools to help us understand
Constructs, but not arbitrary
Theories are inherently open to
revision, refutation and further
Theories are often causal (science)
9.2 p. 341
Perhaps first in 9.5
TESTING OR EVALUATING
Why do we need to determine which theory
Minimal requirement: consistency
Consistency must be internal and external
External consistency also includes
completeness! It cannot fail to include
essential parts of explanandum
THEORY CHOICE, cont.
Minimum requirement cont.
Incompleteness not effective when other
explanations are absurd
Possibility of infinite number of
explanations (theory is
“underdetermined”, evidence does not
dictate what theory is best)
Quantity of evidence: a good indicator
of which theory is better or best
If theory meets consistency requirement, it
is eligible for further testing. If not, it can be
Careful: not refutational
The criteria for adequacy
Requires that there is some way or
method to determine whether theory is
true or false.
Do all components of theory have to
be testable, or only the whole theory?
Soul theory of personal identity, Plato
Theory of witches, moral theory of
Theories are testable when they make
prediction of some event or effect or
phenomenon other than event to be
Sometimes prediction can be a
consequence or outcome
If theory does not do this or predicts the
obvious, we have reason to doubt it.
Theories are more adequate than others if they
predict novel events or phenomenon
Fruitfulness also includes ability to encourage new
research or open up new areas of research
Novel predictions: surprising ones!
Karl Popper and criteria for genuine scientific
Einstein’s theory and its novel predictions: light
around objects appears bent due to curvature of
How much does the theory explain or
If one theory can explain and predict more
than another, that theory is to be preferred
over the other.
Explaining more diverse phenomena
Newton’s theory explained more than
Aristotle’s, Einstein’s more than Newton’s,
Ockham’s razor and parsimony
Theory which makes the fewest assumptions is to
be preferred over others
Notice, comparative nature of theory choice. NO
Conspiracy theories: too many assumptions which
I.E., creationism: assumes the existence of a
creator. But, simpler in other ways!
Ad hoc or auxiliary hypotheses: simplicity is
compromised when these are added to “save” a
A theory which contradicts or goes against
our established knowledge or beliefs is
more likely to be implausible
A warning against novelty! But…
Claim: Vitamin C cures cancer!
Claim: I have made a perpetual motion
machine, or I have produced cold fusion!
Claim: Dowsing or Divining for water works!
SOME CAVEATS FOR
No strict formula. Sometimes one
criterion is weighed more than others
Cannot be used to silence or
discourage radical departures
Criteria is not a proof, only a diagnostic
tool, requiring good judgement
Non-subjective: judgement vs taste!
TEST OR T.E.S.T.
A fully assessment of which
explanations is the best
At the end of the test, we must state
which theory is the most plausible, the
A procedure that requires all the tools
of critical thinking that we have
Step 1: State the theory and check for
Step 2: Assess the evidence, either
presented or not
Step 3: Scrutinize alternative theories.
Step 4: Test the theory using criteria of
State theory in a clear, concise fashion
Apply consistency test (is it eligible for
Evidence? What evidence is given? Is
it reliable, does it commit fallacies, is
the source credible, does it suffer from
a causal confusion, is it consistent with
background knowledge or specialized
Is there evidence disconfirming the
Scrutinize alternative theories.
Might have to formulate or look for
them (thinking outside box)
Goes against our grain, our tendency
to identify with a favorite theory
Using alternative theories for applying
criteria. If we miss this, we cannot take
Complete test by applying criteria of
adequacy. Remember to apply all 5.
Examples on pages 364-68 are instances of
response examples, how to apply the full
Problem of background knowledge!
How much can you be expected to know?
Yardstick: what would you need to know to be
able to judge evidence or fully apply adequacy