Second, it determines the plausibility
of each explanation. By this means
abduction identifies the best explanation for the facts.
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Since no other
explanation accounts for the facts as well as the best, the best explanation is
most probably correct.
Formal Statement
In formal terms abduction can be set out in the following way:
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Observation
B has occurred
Explanation
A causes B is an explanation for the occurrence of B
Strength of Explanation
No other explanation explains the occurrence as well as A
causes B
Conclusion
Therefore, A causes B is probably correct.
Figure 7.1 Form of Abduction
Strength of the Argument
The strength of the argument from abduction rests on two matters. First, ‘A
causes B’ is an explanation for B. Second, ‘A causes B’ is the best available
explanation for B occurring. Clearly this second part of the reasoning depends
on those who propound the argument having made a competent and diligent
search for all possible explanations. A less than diligent or competent search
leaves open the possibility that there is better
undiscovered explanation. By
contrast, diligent or competent search substantially lowers the possibility.
Ordering explanations according to how good they are is not an inherently
precise undertaking. Therefore, the claim for A causes B to be true is made
stronger if it is substantially and demonstrably superior to the next best
alternative; if it is not, the claim for the next best and perhaps other alternatives
strengthens.
Tautology?
Abduction is almost if not actually tautological. The reason for taking the most
plausible or probable explanation is that as the situation is judged it has the
most chance of being right.
Uses
Abduction can potentially be used in any activity where it is necessary to find,
even if tentatively, a causal explanation or law. There are two uses in working
___________________
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Sometimes the term abduction is used just to mean the first part of the
process, generation of hypotheses or explanations, but its more common meaning,
especially in philosophy and computing, is to cover both tasks.
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This is adapted from the model described by John Josephson in “Inductive
Inference in Reasoning and Perception” on www.cse.ohio-state.edu/lair/
Projects/Abduction/abduction.html
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