From: AAAI-82 Proceedings. Copyright ©1982, AAAI (www.aaai.org). All rights reserved.
ARGUMENT
A FUNCTIONAL
MOLECULES:
REPRESENTATION
Lawrence
OF ARGUMENT
STRUCTURE
Birnbaum
Yale University
Department
of Computer
Science
New Haven, Connecticut
Understanding
an utterance
in an argument
requires
determining
the evidential
prior
and subsequent
propositions
argument
crucially
(Birnbaum
et al., 1980; Cohen,
1981).
The memory
representation
of an argument
should,
accordingly,
indicate which propositions
a given proposition
counts as
for (a support
evidence
relation),
and which
turn.
The
viewed
as a network
or attack
sort
of propositions
can
whether
can
connected
graph).
simply
of an argument,
such
argument
cases,
better
chances
probably
lie elsewhere.
be
rebuttal
by support
Although
focus
by the
the
it seems
(and
of the representation
only
understanding
For example,
if)
it
serves
or generating
it seems likely
of the argument
would
of an argument
is useful
One
used
if
to
possible
those
propositions
in an argument
first
be
planning
supposed,
of this sort is not as central
however,
because
as might
engaging
in
can
in
the
is
on
argument
input
structure
is to
occurring
patterns
of
that
encompass
several
propositions,
among
those
are worth trying to attack or
thus
to
be
used
generate
both
to
help
expectations
plan
about
an
rebuttals.
is an
are
opponent’s
between
is described
argument
ad absurdum
an Arab
in Flowers
molecule
argument
inference
et at.,
involving
to attack
rule in support
he cannot
exchange
an
63
of
and an Israeli
accept.
For example,
in a mock argument
over Middle
East
affairs:
[I] Israeli:
Israel can’t negotiate
with the PLO
because they don’t even recognize Israel’s right
to exist.
at
a
an
The attack is effected by showing that
reasoning
can also be used to support
some proposition
that
consider
the following
likely candidates
for an arguer
himself
to attack
or
support,
and thus play a role in planning
a rebuttal.
Explicit
contention
attack
use of a plausible
one of his points.
also
which
structural
must be to
of possible
commonly
relations
(Th e other
of reductio
opponent’s
the
help identify
of
any
planning,
direct
investigate
opponent’s
A stand-off
holds.
should
to
and
kind
structure
rebuttal
of explicit
points
no
specify
which
in the molecule,
rebutting.
be useful in reducing
the number
of
with which an input must be compared
of argument
way
They
would potentially
prior propositions
A representation
good
Two kinds of molecules
have been identified
thus far. The rest of the paper will
illustrate
the use of one of them in understanding
and
how an
relation
a
a key function
opportunistically.
rebuttals,
1982.)
or not an evidential
producing
Thus,
on other
when
support.
structure
should provide
expectations
as to which prior
propositions,
if any, a given input would be likely to
attack,
support,
or be supported
by.
Such information
whether
for
to identify
.and attack
contained
utterance
relates,
via support
or attack
links, to other
propositions
in the argument
(Flowers
et al., 1982;
Reichman,
1981). That is, a representation
of argument
to determine
that input.
is that if a
propositions.
Because of their relatively
fiied structure,
et at., 1982) can be
these argument molecules (Flowers
some
functional
role
in
utterances
in the argument.
that some structural
features
play a role in determining
attention
attempt
support
Identifying
“useful” structural
properties
depends, of
course, on having some notion of what uses they might
have.
In ,a process model of argumentation,
a structural
property
understand
processing
and
hence
enter into such
that
argument
discovered
might
useful
structural
properties,
any
from the specific propositions
they relate.
abstracted
planning,
considerations
this
graphs
et al.,
(McGuire
direct attack on an input is not found at understanding
time, it will most likely be difficult to find one. In these
it in
thus
process
is required
simply
in order to
One implication
of opportunistic
attack
(an
or attack
be motivated
content
the
to ask
possess
support
of an argument
(an argument
relations
to represent
natural
further
or against
propositions
representation
of representation
need
relation)
opportunistic
is an
1981), in which a good rebuttal
to an input can often be
discovered
as a side-effect
of the memory processing
that
relations
it bears to
in the
argument
[2] Arab:
Israel
doesn’t
recognize
the
PLO
[l) is clearly
an
attack
is being
attacked?
is that
the PLO’s
Presumably,
an Israeli would find this
negotiations.
proposition
as unacceptable
as an Arab would find the
Israeli’s original claim.
Thus, if the Arab is successful,
either.
The
some
Israeli’s
kind,
explicit
utterance
but
what
content
exactly
of the utterance
to recognize
Israel is blocking
turn is based on the assumption
is always
this
The
explicit content
by itself does not
force of the utterance
stems instead
to
a prerequisite
the
interpretation
notion
rule
of
which
failure
negotiations,
and this in
that recognition
of some
However,
for negotiations.
sort
appeal
of
The
attack anything.
from an implicit
responsibility,
can
informally
be
using
an
stated
as
neither
disputant
hurting
his own position
called
a stand-off.
for
the PLO
is responsible
utterance,
for blocking
support
of
attribution
negotiations
t
I
<-------
for
to recognize
blocks
Israel
the
has
[l] consists
/
The
becomes
response
to recognize
blocks
negotiations.
recognize
utility
However,
relations
attribution
is similar
to that
Now, the point
using
Israel
the same
as
well
proposed
failure
be
structure
if
such
be
time.
an attack
discovered
in planning
a rebuttal
were possible,
it
opportunistically
If so, there
then
is no need
the possibility
negotiations,
would
on the support
relation
claim that [lb] supports
[la].
no point in trying to support
that
the PLO does indeed
Israel
by Toulmin,
response
the PLO
in
of
would
at
to plan
of attacking
be pointless,
between
[2a] would
entail
an attack
on
attribution
rule, which would be fatal
“unless”
clause of the
(This analysis of support
of the Arab’s
reasoning
can
the
rule.
failure
to recognize
a
[2b] or
because
the
thrust
of the Arab’s argument
is not that [2a] must be
accepted,
but that [2a] must be accepted
if [la] is. An
is not justified.
[lc] represents
[2cl Israel's
is not justified.
of this
if not,
because
Proposition
responsibility
failure
Israel
negotiations.
the Ara.b’s argument,
in this case [2b] or [2c], for example
by arguing that Israel does in fact recognize
the PLO.
attack
\
[lcl The PLO's
to
blocks
[2c] seems remote, and so should not be attempted.
An
attack on the Arab’s claim [2a], that Israel is responsible
attribution
Israel
the PLO
clear when we examine
the Israeli’s options
to [2]. One possibility
is to attack the basis
response;
\
/
failure
[lb] The PLO's
failure
to recognize
is not justified.
presumably
understanding
Responsibility
\
[2b] Israel's
negotiations.
for blocking
/
support
-- which
negotiations.
support:
------>
failure
[lc] The PLO's
is responsible
blocking
attack
I
[lb] The PLO's
investigated
the role of other interpretation
rules of this
sort in ideology-based
reasoning
about political
events.)
[la] The PLO
for
negotiations.
I
is that
this claim, by appeal
to
rule.
(Carbonell,
1981,
Thus, the proper representation
of utterance
of the following fragment
of argument
graph:
blocking
t
et al., 1982)on the Arab
of the utterance
counts as
is a personal attack (Flowers
position.
The explicit content
evidence
in
responsibility
therefore,
is
responsible
negotiations.
to recognize
of the Israeli’s
for the exchange
[2al Israel
is
responsible
follows:
The point
graph
structure:
[la] The PLO
blocking
use this line of reasoning
without
-- which is why this molecule is
The argument
has the following
I
support
Responsibility atttibution:
If an actor performs
some action (or refrains
from performing
some
action)
which causes (prevents)
some state of
affairs, then that actor is responsible
for causing
(blocking)
that state of affairs, unless its action
(failure to act) was justified
by some previous
state of affairs.
can
1958.)
[2] is that,
that
the Israeli
invokes
held
responsible
for
by
in [l],
blocking
the
And finally, there is clearly
[lb] or [ICI, e.g., by proving
refuse to recognize
Israel,
within
the
has
he
evidence.
the point
did not
[2b] and
scope of this stand-off
molecule,
the Israeli actually
only one option if no rebuttai
arises opportunistically:
can attempt
responsible
Arab
between
the
responsibility
to the Israeli’s own
to re-support
for blocking
dispute
it.
Thus,
his claim [la], that the PLO is
negotiations,
using
different
Failing that, he can of course
or change the subject.
The stand-off
molecule
either
can play a similar
concede
role in the
process
of
Consider
exchange:
understanding
the
But
will
the
PLO
PLO
is just
discover
is
a
accounted
argument.
the
draft.
above
a bunch
for
of trying
[2c], the claim
is not justified,
the PLO
response
be
course
Israeli must relate
recognize the PLO
recognize
the
can
in the
he
an
of
his
belief
terrorist
is simply
an
that Israel’s
to memory.
failure to
In doing
Israel’s
by virtue
on
failure
play in determining
how it relates
to the argument
cannot
attack
are possible
the
it
to
of
the
L.,
Arbor,
graph.
there
is a relatively
small
number
out
of molecules,
that
then
R. 1981.
utterance
some
or an
exchange
molecule.
For
example,
“But X does Y also”
stand-off
which
the
typically
an utterance
is probably
a good
The examples
presented
potential
would
some
logical
force,
and
would not.
We can conclude
that arguments
do
possess
useful structural
properties,
abstracted
from the specific
propositions
they encompass.
Many of the ideas in this paper grew
Acknowledgments:
out of discussions
with Rod McGuire.
Mark Burstein and
Steven
Salzberg
provided
useful
comments
Research
pp.
Computer
Press,
Investigation
analysis
of processing
Ann
strategies
Birnbaum,
M.,
McGuire,
arguments
W. Lehnert
and
and
Language
and
the
of
L. 1982.
logic of personal
M. Ringle,
for
In Proceedings
of arguments.
R.,
University
on
for
In essence,
a molecule
rebutting.
about
the logical structure
of an
in a way that makes explicit which
have
Understanding:
UMI
Flowers,
Toulmin,
of a
an argument
can be extremely
useful in focusing attention
propositions
in the argument
graph,
both
responses
CA,
eds.,
Processing,
attacks.
Strategies
Lawrence
for
Erlbaum,
NJ, pp. 275-294.
R.,
Birnbaum,
processing
L.,
and
Flowers,
in arguments.
Vancouver,
B.C.,
M. 1981.
In Proceedings
pp. 58-60.
In
pp.
19-24.
of the form
understanding
and
packages
knowledge
argument
fragment
which
indeed
Stanford,
signal
indication
here show that
R. 1980.
In Proceedings
Modeling
informal
debates.
Reichman,
R. 1981.
Proceedings of the Seventh IJCAI, Vancouver,
B.C.,
molecule.
molecule
relevant
Conference,
Systems.
of the Seventh IJCAI,
A more interesting
features
of an
might
McGuire,
CA, pp. 71-75.
Opportunistic
most straightforward
method would simply be to attempt
to match the templates
of all of them against the most
recent portion of the argument
graph.
approach
would
involve
identifying
and
Subjective
J. 1981.
Adversary
such structures
If it turns
M.,
Stanford,
McGuire,
of recognizing
in an argument.
Foundation
the 19th ACL Conference,
In
the problem
arise
Science
of argumentation.
AAAI
the structural
Hillsdale,
they
by the
NO001475-
MI.
Cohen,
In order to employ the constraints
associated
with
argument
molecules
to understand
or produce responses,
remains
contract
by the National
Flowers,
of Belief
Naturut
there
under
by the Defense
monitored
IST7918463.
First
Models
targets.
when
in part
in part
Agency,
Research
an AI model
Carbonell,
only [2b] and [2c]
link:
and
Projects
313-315.
above analysis
of the Israeli’s
immediately
follows
that
[3]
[2a] or the support
Naval
grant
Towards
This is not the case, however, because the representation
of the Arab’s utterance
[2], when its implications
are
understood,
consists of three distinct
propositions,
plus a
link.
From
for rebuttal,
of
Birnbaum,
Because
this
Arab’s
previous
the
was supported
References
of the fact that
organization.
attack
opportunism,
[2], the
that
is justified,
by
to understand
work
Research
C-1111,
of
utterance,
a possibility
which should always be expected,
it might seem that the stand-off
molecule has no role to
support
options
This
Advanced
under
response
because
so,
in
continuation
Office
[3] Israeli:
terrorists.
This
utterances
following
on an earlier
65
S. 1958.
Press,
The Uses of Argument.
Cambridge,
England.
Cambridge