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In article <1480@crin.crin.fr> marquis@crin.crin.fr (Pierre MARQUIS) writes:
>Could somebody tell me what is the difference between "abduction" (this last
>term was apparently introduced by Alan Bundy) and "induction" ?
>
>Please, send the replies to my mail address.
>Many thanks in advance,
>
>Pierre Marquis
>CRIN (Centre de Recherche en Informatique de Nancy)
>Campus Scientifique
>B.P. 239
>54506 - Vandoeuvre-les-Nancy CEDEX
>France


The first use of the term "abduction" was by the
philosopher/mathmatician Charles Sanders Peirce 1839-1914 (pronounced purse).
Unfortunately I don't have my Peirce stuff handy but I use the
following quote from his works in my work on abductive inference.


\begin{quote}
The first stating of a hypothesis and the entertaining of it, whether
as a simple interrogation or with any degree of confidence, is an
inferential step which I propose to call {\em abduction} [or {\em
retroduction}].

..

Long before I first classed abduction as an inference it was
recognized by logicians that the operation of adopting an explanatory
hypothesis--which is just what abduction is--was subject to certain
conditions. Namely, the hypothesis cannot be admitted even as a
hypothesis, unless it be supposed that it would account for the facts
or some of them. The form of inference, therefore, is this:

\begin{tabular}{l}
	The suprising fact, C, is observed;\\
	But if A were true, C would be a matter of course,\\
	Hence, there is reason to suspect that A is true.
\end{tabular}
\end{quote}

Excuse the tex-isms.

Other useful places to look for discussions are


Gilbert Harmon,"Inference to the Best Explanation", Philosophical
Review (1965)

John Josephson, "Explanation and Induction", Dissertation, Ohio State,
1982.


Charniak and McDermot make mention of abduction throughout their AI
book and a number of researchers do research in the area (Reggia,
Josephson, Charniak, Pearl etc.)

As for the difference between abduction and induction, the discussion
is more complicated. I think the most concise thing to say is that
abduction is a different cut on logic than induction or deduction.
Abduction is driven by trying to explain a set of facts based on
available hypotheses. It is often typified by method of a detective
solving a crime, i.e. here are the crime clues (to be explained) and
here are the facts I can use to explain them.  What is the best
explanation of these clues (in terms of plausiblity, consistency,
whatever parameters you choose) using these facts that I can come up
with.

In finding the explanation, one may use deduction (deriving true
conclusions from premises) or induction (populations from samples) but
one is driven by the process of explanation. How's that?
						>>>Bill<<<


p.s. An interesting, but not always easy to follow (or useful), book
on the detective, Peirce, abduction etc. is

The Sign of Three, Edited by Eco and Sebeok, Indiana Universtiy Press, 1983
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