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From: sarrett@ics.uci.edu (Wendy Sarrett)
Newsgroups: comp.ai,sci.logic
Subject: Re: abduction vs. induction
Message-ID: <14820@paris.ics.uci.edu>
Date: 17 May 89 15:22:18 GMT
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Sender: news@paris.ics.uci.edu
Reply-To: Wendy Sarrett <sarrett@harlie.ics.uci.edu>
Organization: University of California, Irvine - Dept of ICS
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"abduction" can be thought of in two ways. The first is generating
explanations from a conclusion - taking a conclusion and using
background information to build a "proof tree" leading too the
conclusion. The second way to think about it is as the opposite of
deduction i.e. if you have A -> B then you turn the arrow around and
when you see B, you infer that A must be true.

"induction" is the process of generalizing from lots of examples. For
example, suppose you see a number of examples of ducks and they are
all grey ( isa-duck -> grey) then you would conclude for all ducks,
isa-duck -> grey.  Note that there is also induction in mathematics
where if you can show (where A is a set) (1 in A) and (n in A) -> (n+1
in A) then you can conclude for all n, n in A.

Note that both "abduction" and "induction" are not "safe" forms of
inference as "deduction" is. (i.e. you can't be 100% certain your
inference is correct)

Hope this answers your question,
Wendy 
(sarrett@ics.uci.edu)
Department of Information and Computer Science
University of California, Irvine