kean@cs.ubc.ca (Alex Kean) (05/07/91)
First, thank you for all the replies. The "explanations" are very
helpful and appreciated. The origin of the word in Greek, as pointed
out by Pierre Marquis, is from Aristotle [see also peirce32, pp 497].
The name
\'\alpha \pi \alpha \gamma \omega \gamma \'\eta ==> (apagogy)
means what Peirce called "abduction" and
\epsilon \pi \alpha \gamma \omega \gamma \'\eta ==> (epagogy)
means "deduction". The \'\alpha ( a ) is like ( un- ) in English and
thus (apagogy) is the opposite of (epagogy). I guess Paul Scott and
Michael Covington might be right is saying that Peirce was translating
the word (apagogy) from Greek and "ab-duction" seemed the right
matching structure.
Another key observation (at least for me), as pointed out by Timothy
Cain, is that the minor premiss and the conclusion are only PROBABLE.
This is also emphasized in Peirce text [Peirce32, pp 53]. I always
thought of "abduction" as "deduction" in reverse, which is true in
some sense, but the difference is that the "explanations" from
"abduction" is not necessary a consequence of the facts or even true.
This is different from "deduction" where each inference step (except
the axioms) is a logical consequence of the facts.
Thank you again for all the replies.
Best Regards,
Alex Kean <kean@cs.ubc.ca>
Department of Computer Science
University of British Columbia
#333-6356 Agricultural Road,
Vancouver, British Columbia
Canada V6T 1Z2
Tel# (604)-822-4912
@book{peirce32,
author = {Charles Sanders Peirce},
title = {{Collected Papers of Charles Sanders Peirce}},
publisher = {Harvard University Press},
volume = 2,
year = 1932,
note = {Editors --- Charles Hartshorne and Paul Weiss}
}
===============
1) FROM: Timothy D. Cain <cain@ics.uci.edu>
First, let me say that my New Webster's dictionary includes the definition
"in logic, a syllogism, the minor premise and conclusion of which
are only probable"
Not exactly what I call abduction, but closer the anatomical definition!
Forming a complete proof (all of the leaves of the proof are known to
be true) is a deductive process, not an abductive one. Abduction
provides a plausible proof, where one or more of the leaves of the
proof are not known to be true (or at least, their certainty is not
100%). If any proof of a known conclusion requires the reasoner to
make an assumption, that's a good sign that abductive reasoning is
being used.
A lot of people say Sherlock Holmes performed deduction, but I
disagree. He made MANY assumptions to back up his conclusions, which
is an abductive process (or at the very least, it's assumptive
deduction, but that's a whole new can of worms!).
==============
2) FROM: Michael A. Covington <mcovingt@athena.cs.uga.edu>
I always thought the word "abductive" was chosen rather arbitrarily
because it resembles "inductive" and "deductive".
==============
3) FROM: Paul Scott <scotp@essex.ac.uk>
While I don't actually know why Peirce chose this term, I can offer a
plausible guess:
The term 'deduction' derives from 'ducere' (lead) prefixed by 'de'
which, in this case, means 'from'. I guess that Peirce wanted another
term to denote a different way in which one proposition may follow
from another. So he looked round for another prefix that could mean
'from'. He found 'ab' -- hence 'abduction'.
You will note that this explanation is itself derived through
abductive reasoning!
==============
4) FROM: Raul Valdes-Perez <valdes@cs.cmu.edu>
I would suggest some selective reading in Charles S. Peirce, "Essays
in the Philosophy of Science," American Heritage Series, 1957.
I did some reading there, and discovered quite muddled uses of the
term abduction by Peirce. In one essay he seems to mean one thing,
and in a second he means another. Peirce introduced the term because
he wanted to speak of scientific processes other than "induction,"
understood as merely formulating generalized laws from data. For
example, he wished to discuss the proposal of explanatory theories,
such as theories that provide a physical mechanism giving rise to
observed data, in which data are qualitatively quite distinct from
theory. Such an abduction would be the proposal of the mechanism
underlying blood circulation in the body, starting from data on blood
properties, what happens when an artery is artifically constricted by
a tight knot (you get a bulge on one side but not the other), etc.
Peirce also used synonyms for `abduction,' such as the `method of
hypothesis.'
==============
5) FROM: Charles Elkan <elkan@cs.UCSD.EDU>
Abduction in Pierce's meaning will be found in larger dictionaries.
It is common to twist an ordinary word into a technical term, so I
don't think it's worthwhile to debate whether abduction was the best
word to be twisted.
Abduction means reasoning from a proposition B to a proposition A such
that A -> B. The arrow may be causation or another type of
implication. Deduction would be reasoning from A to B.
Both deduction and abduction can be yes/no or constructive. If I tell
you that A -> B and B, and I ask "A?" then you will do yes/no
abduction to answer my question. If I tell you that A -> B and B, and
I ask what follows, you will do constructive abduction. (Note that I
am using constructive as an ordinary English word here, simply because
I don't know a widely-accepted technical term for this distinction.)
==============
6) FROM: Pierre Marquis <marquis@loria.crin.fr>
The term "Abduction" has been introduced by Aristotle in its First
Analytics. In this book, Aristotle presents a theory of induction (II,
23) and a theory of abduction (II, 25) in a syllogistic frame.
Synonyms are apagogy (Aristotle) and (I think) retroduction (Peirce).
==============
7) FROM: Mike <mtanner@gmuvax2.gmu.edu>
Peirce also used the term "retroduction" for the same things he used
"abduction" for. I don't really know his reasons for the term, but
retroduction gives the image of something like "deduction in the other
direction". I.e., the hypothesis generation part of the
hypothetico-deductive method, but not merely generating any
hypothesis, but hypotheses of particular kinds.
==============mcovingt@athena.cs.uga.edu (Michael A. Covington) (05/07/91)
In article <1991May6.173412.11283@cs.ubc.ca> kean@cs.ubc.ca (Alex Kean) writes: > >First, thank you for all the replies. The "explanations" are very >helpful and appreciated. The origin of the word in Greek, as pointed >out by Pierre Marquis, is from Aristotle [see also peirce32, pp 497]. >The name > \'\alpha \pi \alpha \gamma \omega \gamma \'\eta ==> (apagogy) >means what Peirce called "abduction" and > \epsilon \pi \alpha \gamma \omega \gamma \'\eta ==> (epagogy) >means "deduction". The \'\alpha ( a ) is like ( un- ) in English and >thus (apagogy) is the opposite of (epagogy). I guess Paul Scott and No; the prefix in "apagogy" is "apo-" ("from"), not "a(n)-" ("not"). So apo+agoge = ab+ductio = abduction (a Greek-to-Latin literal translation). -- ------------------------------------------------------- Michael A. Covington | Artificial Intelligence Programs The University of Georgia | Athens, GA 30602 U.S.A. -------------------------------------------------------
newsuser@oliver.SUBLINK.ORG (Ugo Cei) (05/09/91)
kean@cs.ubc.ca (Alex Kean) writes: >The name > > \'\alpha \pi \alpha \gamma \omega \gamma \'\eta ==> (apagogy) >means what Peirce called "abduction" and > \epsilon \pi \alpha \gamma \omega \gamma \'\eta ==> (epagogy) >means "deduction". The \'\alpha ( a ) is like ( un- ) in English and >thus (apagogy) is the opposite of (epagogy). Not at all ! The alpha in ``apagwg\'h'' [substitute omega for `w' and eta for `h', using a full TeX-like notation is just too clumsy for me] is not a ``privative alpha'', that would indeed mean a negation of the concept. Where would the ``pi'' come from, in that case ? Rather, the word is formed from ``ap\'o'' (``from'' in current English, however the root is the same as of Sanskrit ``apa'', Latin ``ab'', English ``of'') and ``\'agw'' (English ``I lead'', Sanskrit ``ajati'', Latin ``ago''), thus meaning ``the act of leading away'', which in Latin is spelled ``abductio'', from ``abducere'', Greek ``ap-agage\~in''. On the other side, ``epagwg\'h'' is made from ``ep\'i'' and ``\'agw'', with the meanings of ``the act of leading into/onto''. Moreover, I think that in Aristotles, the word is used with the meaning of ``reasoning by induction'' and not ``deduction'', but I have no proofs to back this claim other than common sense and a reference in my Greek-Italian vocabulary. Whew! I never thought that the Greek I took while at ``Liceo Classico'' would have served me in an occasion like this. -- **************** | Ugo Cei | home: newsuser@oliver.sublink.org * OLIVER * | Via Colombo 7 | office: cei@ipvvis.unipv.it **************** | 27100 Pavia ITALY | "Real Programs Dump Core"