r ISSN 0824-2577 
infdr."tlal logic 

vol. vi, no. 3 eds. J. Anthony Blair & Ralph H. Johnson December 1984 

-
contents r UnilJersity of Windsor 

AUG 6 1986 

from the editors 
We apologize to our subscribers for the long delay 

in getting this issue out. It was partly caused by a 
forced change of typesetters. 

Starting with Volume VII, Number 1, Informal 
Logic will have a new format. Thanks to a grant from 

leddV libr3r'j _I 
ARTICLES l __ "':~':'----I INFORMAL LOGIC is published by the editors three times a year, in Winter, Spring and Summer. All sub-

scriptions begin with the Winter number; later sub-
scribers receive the current volume's back issues. 
Rates: Individuals: Canada & U.S.A. $10/Volume 
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$6/lssue; Other $19/Volume $8/lssue (includes air-
mail postage). 

Observation Ability: Determining and Extending 
Its Presence 

Stephen P. Norris and Ruth King. . . . . . . . . . . . 3 
Rhetoric, Argumentation and Logic 

George Yoos . . . . . . . . . . . ............ 10 
A Rhetorical Conception of Rationality 

Richard J. Burke ......................... 17 
The Rhetoric of Action Description: 
Ambiguity in Intentional Reference 

Randal Marlin ........................... 26 

RESPONSES 
John Nolt's Inductive Reasoning Test 

Howard Kahane ......................... 30 
Degrees of Validity and Ratios of 
Conceivable Worlds 

Stephen N. Thomas ...................... 31 
Reply to Englebretsen 

James Freeman ......................... 34 
Reply to Fred Johnson 

G .A. Spangler . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 
McPeck on Critical Thinking: A Reply 

David B. Annis and linda F. Annis ......... 42 

NOTE 
Informal Logic in China 
J~nN •............................... 44 

ANNOUNCEMENTS 
Conferences ... , .......................... 46 
Other Items of Interest ...................... 48 

BOOKS RECEIVED ........................ 49 

Managing Editor: Peter F. Wilkinson. 
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3P4. 



the Dean of Arts at the University of Windsor, Dr. 
Jerome V. Brown, our subscription rate for 1985 will 
remain unchanged, even with the extra costs of 
acquiring a more "journal" look: $10 per volume to 
individuals, $14 to institutions. Subscriptions for 
Volume VII are now due. We will experience further 
delays in the process of changing over, but we hope 
to be onto a reliable schedule by Fall 1985. 

We are delighted to welcome Dr. Maurice Finoc-
chiaro of the University of Nevada at Las Vegas 
to the Editorial Board. Editors, authors and readers 
alike will benefit from his sympathetic but penetrat-
ing critical services. 

While we receive a steady flow of articles submit-
ted for publication, we still need to use this space 
to solicit work, and encourage you, colleagues, to 
put your thoughts on paper. Our decision to publish 
the proceedings of the Second International Sympo-
sium on Informal Logic over a number of issues has 
created a small, temporary backlog that will be over 
by the end of this year. While there will, in the in-
terim, be a delay in the publication of articles, it 
remains short as journals go-about 12 months. And 
we will still run comments and replies quickly-in 
the issue following or the one after that. 

In this issue, we have two articles which deal with 
rhetoric: George Yoos's paper, "Logic, Rhetoric and 
Argument" was presented at the Second Interna-
tional Symposium on Informal Logic. We are pleased 
to welcome Professor Burke to these pages; his art-
icle is "A Rhetorical Conception of Rationality." 
Questions we ponder when thinking about the nature 
of informal logic are "What is rhetoric?" and "What 

2 

relationship is there between rhetoric and informal 
logic: between speech communication and informal 
logic?" Clearly, one topic which interests both part-
ies is argumentation; our brethren in speech com-
munication and rhetoric have been actively involved 
in research in this area for many years and have 
been quicker to see the potential of the work done by 
philosophers such as Stephen Toulmin and Chaim 
Perelman than have logicians and other philoso-
phers. 

Elsewhere in this issue you will find several res-
ponses to articles and notes which have appeared 
in previous issues of Informal Logic and announce-
ments of several conferences worthy of note. 0 

corrections 

Please note the correct spelling of Maurice Finoc-
chiaro's name. The editors apologize to Dr. Finoc-

chiaro for the error which appeared in vi.2, p. 1 
(Contents) . 

And please note the correct spelling of Stephen N. 
Thomas's name, and the correct date of publication 
of his text, Practical Reasoning in Natural Language 
(Englewood Cliffs, NJ: Prentice Hall, Inc.) First 
Edition, 1973; Second Edition, 1981. The editors 
apologize to Dr. Thomas for the errors which ap-
peared in John Nolt's, "Possible Worlds and Im-
.agination in Informal Logic", vi.2, p. 15 and p. 17.0 

editorial boa rd 

Robert Binkley 
University of Western Ontario 

Robert Ennis 
University of Illinois at 
Champaign-Urbana 

Maurice Finocchiaro 
University of Nevada-
Las Vegas 

Trudy Govier 
University of Calgary 

Merrill Hintikka 
Florida State University. 

David Hitchcock 
McMaster University 

Howard Kahane 
University of Maryland-
Baltimore Country 

Richard Paul 
Sonoma State University 

Robert C. Pi nto 
University of Windsor 

Nicholas Rescher 
University of Pittsburgh 

Michael Scriven 
University of Western Australia 

Douglas Walton 
University of Winnipeg 

John Woods 
University of Lethbridge 

George Yoos 
St. Cloud State University