Reflections on Henry Webb Johnstone, Jr. 

RICHARD B. ANGELL Wayne State University 

Abstract: Personal reflections on the philo-
sophical career of Henry Johnstone, B.S. 
Haverford College, 1942, and Ph.D. 
Harvard, 1950, professor at Williams Col-
lege 1948-1952 and Pennsylvania State 
University, 1952 - 2000. Founder and edi-
tor of Philosophy and Rhetoric, Johnstone 
wrote eight books, including two logic texts, 
three monographs, and over 150 articles or 
reviews. The focus is on his efforts to re-
solve problems stemming from the conflict 
between the logical empiricism Johnstone 
embraced in his dissertation, and the argu-
ments of his absolute idealist colleagues at 
Williams, efforts he pursued in Philosophy 
and Argument (1959), and Validity and 
Rhetoric in Philosophical Argument (1978). 

Resume: On presente des refiexions 
personnelles sur la carriere philosophique 
d'Henry Johnstone: B.S. au College 
Haverford, 1942, Ph.D, I' Universite 
Harvard; professeur au College Williams de 
1948·1952 et I 'Universite Pennsylvania 
State de 1952-2000. II a ete Ie fondateur et 
Cditeur de la revue Philosophy and Rhetoric, 
il a redig.: huit Iivres, deux manuels de logique, 
trois monographies, et plus de 150 articles 
ou comptes rendus. On concentre sur. ses 
efforts de resoudre les problemes qui 
surgissent du conflit entre I'empiricisme 
logique adopte dans sa these doctorale et les 
arguments de ses collegues idealistes au 
College Williams, et sur ses efforts poursuivis 
dans Philosophy and Argument (1959) et 
Validity and Rhetoric in Philosophical Argu-
ment (1978). 

Keywords: Henry Johnstone, Jr., Harvard University, validity, rhetoric, logical positiv-
ism, philosophical argument, argumentum ad hominem, persuasion. 

Henry Webb Johnstone, Jr. was born February 22, 1920 of affluent parents in 
Montclair, New Jersey. As an adolescent he went to Hill School where he got a 
good grounding in Latin and became interested in reading far eastern philosophy. 
He received a B.S. in Philosophy from Haverford College in 1942, and a Ph.D. in 
Philosophy from Harvard in 1950. After an instructorship at Williams College from 
1948-1952, he joined the faculty of Pennsylvania State University in 1952. There 
he remained for 48 years, becoming Professor 1961-1984 and an active Professor 
Emeritus from 1984-2000. He was a visiting professor at the University of Brus-
sels, Belgium (1957), at Trinity College, Dublin, (1960-1961 ), at Bonn, Germany 
(1969) and the American University in Beirut, Lebanon (1971-1972) and also 
lectured in Italy, France, Finland, England and Holland. He was a founder of the 
Journal, Philosophy and Rhetoric, which he edited from 1968 to 1976 and again 
from 1987 to 1998. He also became editor of the revived Journal of Speculative 
Philosophy in 1987. His vita includes eight books, three monographs, and over 
150 articles or reviews. He wrote two logic texts (1954, 1962), but his most 

©lnjormaLLogic Vol. 21, No.1 (2001): pp.I·9. 



2 Richard B. Angell 

original works were Philosophy and Argument (1959), The Problem of the Self 
(1970), and Validity and Rhetoric in Philosophical Argument (1978). 

Back of this imposing array of accomplishments, was a moderately patrician 
man with a wry sense of humor, a rich interest in music and travel, and an inner 
struggle in pursuit of philosophical integrity. The inner struggle began at Williams 
after he left Harvard. 

I knew Henry Johnstone as a graduate student at Harvard in 1946 to 1948. We 
were both members of that fortunate group discharged from the U.S. Army fol-
lowing World War II, whose graduate education was made possible by the GI Bill 
of Rights. We and our fellows were model students; we knew why we were there, 
what we wanted, and were seriously devoted to our subjects. 

When I arrived at Cambridge I was told by the Philosophy Department Secre-
tary, Ruth Allen, that philosophy Professor Raphael Demos had some extra rooms 
in his house that would be rented to graduate students. I quickly established my-
self on the third floor, and soon found that the adjacent room was occupied by 
'Hank' Johnstone. For the next two years we went to classes, dining halls and 
many social occasions together, talking philosophy and enjoying the rich cultural 
environment of Cambridge and Boston. 

The Demos home was a large, brown-shingled house on Francis A venue. Hank's 
initial response was to be a bit overwhelmed by the tradition. Our backyard was 
back-to-back with William James's brown-shingled house, in which his son still 
lived. The desk in my room had been Josiah Royce's desk. The Demos's had been 
friends with the Alfred North Whiteheads, and his widow still gave teas for stu-
dents, at least one of which we attended. 

However, in the philosophical climate at Harvard at that time, Alfred North 
Whitehead's philosophy had little impact outside of his work with Russell on 
Principia Mathematica (1910), Russell was perhaps the most pervasive external 
influence. C. I. Lewis and W. V. O. Quine were the currently most influential 
philosophers in the department, though our mentors also included Donald Williams, 
a straightforward materialist, John Wild, a proponent of perennial Aristotelian phi-
losophy, Henry Aiken (British philosophy), H.M. Sheffer (logic) and Demos (Plato). 

Quine's "Elementary Logic" was the mandatory logic course, and his Math-
ematical Logic (1940), which sought to clarify and improve Principia Mathematica, 
was the primary advanced course in logic. We took C. I. Lewis's course in Theory 
of Knowledge, while reading his Analysis of Knowledge and Valuation in page 
proof; it came out later in 1946. This was a very thoughtful effort to establish the 
relationship between logic, empirical knowledge and valuation. Lewis's earlier at-
tack on the "material implication" of Principia Mathematica and his proposed 
alternative of a logic based on "strict implication" had not won the day in logic. 
Quine defended Principia by separating "logical implication" from the "truth-func-
tional conditional," thus removing confusions stemming from Lewis's (and Russell 
and Whitehead's) early characterization of '~' as "material implication" (see 
Mathematical Logic, §5).1 



Reflections on H W. Johnstone, Jr. 3 

Behind the developments at Harvard in those years was the challenge oflogical 
positivism. This movement had flourished with journals, books and congresses on 
the Unity of Science in the 1930s before World War II and was still alive immedi-
ately after the war. It was inspired by Wittgenstein's Tractatus Logico-Philosophicus 
(1922), and spurred by Carnap's missionary zeal in books like Philosophy and 
Logical Syntax (1935) and Meaning and Necessity (1947), It was characterized by 
the beliefthat in so far as philosophical problems are genuine they can be solved by 
logical analysis oflanguage (using the logic of Principia Mathematica), a blat;lket 
rejection of metaphysics as meaningless, and a reliance on scientific method in all 
matters of fact. They thought they had brought to an end the purported lack of 
progress in philosophy due to the fact that no metaphysical system of philosophy 
could establish itself against the arguments of opposing systems. Though the Vi-
enna Circle had broken up, the movement was not dead. Ayer's second edition of 
Language, Truth and Logic came out in 1946 while we were at Harvard. I remem-
ber at a lecture Ayer gave at Harvard, Demos asked him rhetorically, "Does God 
exist?" and Ayer, in the best positivist stance answered coldly, "I don't know what 
you mean." 

It would be very wrong to describe the Harvard Department of that period as 
being dominated by logical positivism. The shadows of Alfred North Whitehead, 
William James the pragmatist, Josiah Royce and William Hocking the idealists, as 
well as Santayana the materialist, hung over us. c.l. Lewis told me when I was 
preparing a paper about him for the Philosophy Club, that Royce was the one who 
influenced him most. Whitehead was the teacher that brought Quine under the 
spell of Principia Mathematica. And all were touched to some degree by James's 
pragmatism and radical empiricism. To pass comprehensives, graduate students 
had to master courses on ethics, metaphysics, Plato, Aristotle, British Empiricism 
and Continental Rationalism. The diversity ofthe faculty testified to the variety of 
approaches we encountered. 

Nevertheless, the ideas motivating our dissertations came from the new math-
ematical logic, philosophical analysis of language, and empiricism. Johnstone's 
dissertation was entitled "The Grammar of the Sense Data Language"; mine was 
"Language, Designata and Truth: a Prolegomenon to a Pragmatic Rationalism." 
Johnstone was closer to realism, and not much influenced by James. 

It was a period before contemporary existentialism began to take hold philo-
sophically in this country. I remember just before leaving Harvard, reading Sartre's 
little book, Existentialism, and being unable to make any sense of it. It also pre-
ceded the spread of "ordinary language" philosophy spurred by Wittgenstein's 
about-face in Philosophical Investigations (1952), where he rejected his first method 
of linguistic analysis based on Principia Mathematica and started a general move 
away from the logical empiricism which characterized our days at Harvard. It 
even predated Quine'S famous "Two Dogmas of Empiricism" (1951). It was a 
period before computers, artificial intelligence, possible world semantics, and cog-
nitive psychology. And of course it was long before the rise of deconstructionism 



4 Richard B. Angell 

and post-modernism on the continent of Europe. And it was long before disillusion 
with formal logic led to the popularity of informal logic, celebrated by the founding 
of the journal Informal Logic in 1984. 

Those years at Harvard were very stimulating, crucial years for both of us. 
They were also happy years. Henry had begun a collection of classical music 
records, and would buy a jug of red wine and invite his friends to join him on 
Friday evenings to listen to Vivaldi, Bach, and Beethoven among others. Among 
those who came were his close friends Bill Craig and Henry Hiz, who would later 
be colleagues at Penn State before they departed for Berkeley and the University of 
Pennsylvania respectively. Among his other friends of that period were Hoa Wong 
(who stayed at Harvard, then went to Rockefeller University), Peter Glassen (Uni-
versity of Manitoba), Jim Oliver (Chair, University of South Carolina). 

In his first year or so, Henry became romantically involved with one or two 
graduate students who attended his soirees. But in his second year his attention 
became focused on another philosophy graduate student, Margery Coffin, a <PPK 
philosophy major from Colorado College. She got her masters degree in 1948 and 
was offered a job at a nearby liberal arts college in Massachusetts, but married 
Henry instead on July 17th of that year. I was best man at their wedding, in 
Milwaukee. 

In the fall of 1948 our ways parted. Henry secured an appointment as instruc-
tor at Williams College, so Henry and Margery moved to Williamstown, MA. In the 
fall of 1949 I went with my wife, who had been closely connected to the Demos 
household, to Florida State University. We visited the Johnstones at Williamstown, 
at Henry's family's summer place, Honest Point Farm, on the Eastern Shore of 
Maryland, and at Penn State. We exchanged Christmas cards and books from time 
to time. Hank turned up unexpectedly at my retirement party in 1989 at Wayne 
State University and in July 1998 he and Margery came to Kendal, where I lived, to 
celebrate their 50th wedding anniversary. 

But on leaving Harvard we went different ways philosophically and I did not 
follow Henry's work in great detail, nor did he mine. Perhaps I should leave dis-
cussions of his work to those who have followed it more closely, but having 
reviewed Henry's long career in preparing this article, I can not resist adding a few 
comments on his subsequent developments in the light of what I knew of him. 

At Williams, Henry was shocked to find that Hegelian Idealism was alive and 
kicking in the person of Professor J. William Miller and his colleagues. In the 
Introduction of Validity and Rhetoric in Philosophical Argument, Johnstone de-
scribes "the Angst, the desperation" of that encounter. As the result of his total 
immersion in the graduate program at Harvard, he was "not only deeply commit-
ted to empiricism, but also under the impression that any philosopher in his right 
mind would be committed to it." He found that his colleagues at Williams were not 
only not empiricists, 

They were adherents to a position I thought had long since been decisively 
refuted; to wit, Absolute Idealism. They read Hegel long after Hegel-as I 



Reflections on H. W Johnstone, Jr. 5 

had been led to believe-had been consigned to the museum of philosophi-
cal aberrations and curiosities. Even worse they seemed to have no apprecia-
tion of the advances which had been made by modern empiricism ... In short, 
my new colleagues seemed to me to be anachronisms and quacks. 

So I set out to refute them .... (1978, p.l) 

In his dissertation Johnstone had espoused empiricism as the theory that "eve-
rything we know can be analysed into sensory or perceptual data" (p. 20). "Sense 
data must be assumed to justify any occurrences of empirical knowledge" (p. 72). 
"The relation between sense data and knowledge is in fact logical; it is precisely 
similar to the relation between postulate and theorem in mathematics" (p. 70, §41). 
Sense data are necessary conditions of empirical knowledge; axioms are neces-
sary conditions of mathematical knowledge (p. 72). "No one who is rational," he 
wrote, "can fail to see the truth of a logical tautology, a mathematical theorem, or 
a proven empirical fact" (p. 5). "No fact can be better known to me than that I am 
now sitting at this desk ... I can not conceive of any context of objects, unknown 
to me now, which would invalidate its claim to be objective. Theoretical doubt-
e.g., that maybe it is an illusion that I am sitting at my desk, or even that maybe all 
of my conscious experience is an illusion-is meaningless because it has no prac-
tical consequences" (p. 36, § 15). "Practical knowledge is knowledge which satis-
fies a system of purposes" (p. 41, §] 9). "Empirical and practical knowledge are 
indistinguishable" (§31). His thepry is a "finite context theory" vs. the idealist's 
"infinite context theory" (p. 24)) 

His thesis was of course far more subtle and complex than these frag-
ments, but they suggest the mind-set he brought to Williams. His new colleagues, 
notably Professor Miller, didn't buy it. Johnstone asked what sense impressions 
supported their ideas. Instead of retreating, they asked him questions about sense-
impressions. Since he granted that sense-impressions were only qualities, he had 
to admit they couldn't imply anything. When he said that a sense quality was what 
he experienced here and now, they pointed out that "here" and "now" are abstrac-
tions. They rejected his view that empiricism and Russell's logic provided the final 
step in solving the problems of philosophy; rather it was just one phase in a long 
dialectical history of philosophical positions, each theory arising out of opposition 
to preceding theories and giving rise to new opposing theories. 

None of my attempts at refutation was successful. Much more important, 
however, was my realization, after a painful period during which it was nearly 
impossible to carry forward any intellectual project at all, that I had been 
caught up in the very idealism that had once seemed so easy to refute. 

With this realization came the need to reflect on the etiology of the deep 
change in my philosophical position. Somehow, my colleagues had argued 
me into idealism. I wanted to understand the power of their arguments. My 
reflections took the form of my early writings on philosophical argumenta-
tion .... (1978, p. 2) 

The book from which these passages were taken is dedicated to his two abso-
lute idealist colleagues at Williams College, Professors Bill Miller and Larry Beals. 



6 Richard B. Angell 

It contains sixteen of his most important and influential essays, and chronicles his 
development up to 1978. In it he remarks that few people other than his erstwhile 
colleagues realize his debt to the idealists in his theory of argumentation; e.g., "that 
when I said that I thought that philosophical argument were sui generis-not to be 
judged by the standards of argumentation in science and everyday discourse-I 
was expressing much the same idea that can be expressed by saying that the 
Hegelian dialectic is not to be judged by the standards of argumentation in science 
and everyday discourse." 

The theory of philosophical argument which he developed was that philosophi-
cal argument was sui generis and always ad hominem. He used the term 'ad 
hominem' in a special sense. Many elementary logic textbooks today treat 
"Argumentum ad hominem" as a fallacy-the fallacy of attacking the character or 
credibility of the person who advances the argument instead ofthe argument itself 
(e.g., Salmon 1989, p. 75). However Johnstone's use of "ad hominem" is based 
on a quite different definition, from Richard Whately's Elements of Logic (1838). 
There it is an argument which proves your position to an opponent by showing 
that " ... this man is bound to admit it, in conformity to his principles of reasoning, 
or consistency with his own conduct, situation, &c." In order that his idealist 
opponents could convince Johnstone, they had to draw upon Johnstone's own 
philosophical presuppositions-for example his view that sense data were quali-
ties, and that "The relation between sense data and knowledge is in fact logical; it 
is precisely similar to the relation between postulate and theorem in mathematics," 
which he held in his dissertation. If he was to convince idealists to adopt his 
philosophical position, he had to present an argument with their basic presupposi-
tions and principles as premisses. Arguments from the other person's principles 
could be valid or invalid; if valid the other philosopher would be bound to accept 
them. 

However, this was not the end of it. He later asked what constitutes "validity"? 
He assumed an argument is valid "only when it is impossible for all the premisses 
to be true while the conclusion is false" (Johnstone 1978, p. 47) , i.e., if the 
negation of the conclusion is inconsistent with the premisses. But what is "incon-
sistency"? There are different theories of logic with different criteria of inconsist-
ency, and the different theories of logic are embedded in different philosophical 
systems. Thus, it is clear that "inconsistency" is not just a matter of fact. The 
realist in logic argues against the pragmatist or idealist in logic, each having differ-
ent criteria of inconSistency and validity, yet each basing their argument somehow 
on appealing to the concept of validity held by the other. At first he had held that 
consistency and rationality were objective properties. But this conflicted with his 
theory that all philosophical arguments are ad hominem because then every philo-
sophical argument would be solvable based on a universal objective principle. For 
a while in maintaining his ad hominem theory he held the view just mentioned. that 
validity and consistency were philosophical concepts that could differ in different 
philosophical systems. But how then could they both be appealing to the same 



Reflections on H. W Johnstone, Jr, 7 

validity? LatJ he held that concern for validity was a regulative principle guiding 
both parties in philosophical argumentation, though opposing philosophers might 
not agree on just what validity is. 

Johnstone's book, Philosophy and Argument, appeared in 1959. It drew upon 
nine of his earlier articles, beginning with "Philosophy and Argumentum ad Hom-
inem" from the Journal o/Philosophy (1952). His second book in this area, Valid-
ity and Rhetoric in Philosophical Argument, was published in 1978. It covered the 
second phase of his philosophical journey-Johnstone's remarkable involvement 
with philosophy and rhetoric which grew out of his theory of ad hominem argu-
ments. This was a gutsy move on his part, since this cross-disciplinary area was 
not recognized by the philosophical establishment. His entry into it was on novel 
grounds and influenced both disciplines. 

In 196 I, while Johnstone was acting chairman of the Philosophy Department 
at Penn State, Bob Oliver, Chairman of the Speech Department, suggested that 
they make a joint appointment in rhetoric and philosophy. This didn't work out 
though they approached some prospects (Perelman and Natanson) together. Be-
sides, Johnstone's initial view of rhetoric was not favorable. He wrote a chapter 
on "Persuasion and Validity in Philosophy" in 1965 (1965, Ch. 9) in which, he later 
said, "I depict[ed] rhetoric in the worst possible light" (1965, p. 2). In that paper 
he held that (1) "the aim of the merely persuasive speaker is to secure acceptance 
to his point of view," (2) "rhetoric is perfect only when it perfectly conceals its 
own use," (3) "To be assured of effectiveness, a speaker must operate unilaterally 
upon his audience." He asserted that "No philosopher worthy of the name would 
wish to secure assent to his position through techniques concealed from his audi-
ence," and held that in philosophical argumentation arguments must be straight-
forward and bilateral (I965, p.2). 

Oliver, however, noticing that Johnstone was interested in rhetoric, succeeded 
in getting him to speak on the subject and to collaborate in arranging a conference 
on philosophy and rhetoric in 1965 with five or six speakers from each discipline 
reading papers. Out of this mutual involvement came the journal, Philosophy and 
Rhetoric. The first issue, with Johnstone as editor, appeared in April, 1968. His 
attitude towards Rhetoric changed, and in 1978 he wrote, "My present position on 
the nature of rhetoric and its role in philosophical argumentation is just about the 
opposite of my earlier one." 

Perhaps his most influential article for people in Speech was, "The Relevance 
of Rhetoric to Philosophy and of Philosophy to Rhetoric" (1965, p. 2). There he 
wrote that rhetoric was relevant to philosophy in the same way in which science, 
politics and morals are relevant to philosophy. Just as philosophy must develop 
philosophy of science, political and social philosophy and philosophy of morals, it 
must develop a philosophy of rhetoric. For rhetoric deals with persuasion, and 
persuasion is a necessary mode of experience. Man is not only a scientific animal, 
a political animal and a moral animal; man is a "persuading and persuaded animal." 



8 Richard B. Angell 

On the other hand, philosophy is relevant to rhetoric, just because philosophical 
examination "becomes imperative in times when the foundations of the subject 
poses a problem." He noted that awesome persuasive powers often occur in un-
scrupulous hands. How do we draw the line between responsible and irresponsible 
persuasion? This is not a problem which can be solved by rhetoric, but requires 
philosophy. He suggests an answer that goes back to his earlier objections: "The 
most responsible forms of persuasion" involve a "bilateral attempt to persuade, in 
which no rhetorical device is concealed" (1965, p. 43). 

Johnstone's concept of ad hominem argumentation had special resonnance for 
rhetoric, since the attempt to persuade is most successful when one argues from 
premisses that the audience accepts. Johnstone enriched this ancient point. Re-
sponsible rhetoric will seek to be valid argumentation in a broad sense of valid. It 
will conceive of itself as bilateral, addressed to listeners who can respond with 
doubts and challenges. The audience should be viewed, not as objects to be ma-
nipulated, but as persons capable of accepting or rejecting premisses and conclu-
sions 

Johnstone's interest in informal logic was a natural consequence of his interest 
in the philosophy of rhetoric. Having written two books on formal logic, he was 
friendly to informal logic because he was concerned with validity and came to 
consider validity as being more than the formal validity of mathematical logic. 
Appealing to ordinary uses of 'valid' he added requirements of "forcefulness" and 
relevance, and would include as "valid" those arguments which showed another 
argument to be invalid, as in ad hominem argumentation. 

Around 1975, at the age of 55, he became interested in the Classics, especially 
Homer and the pre-Socratics. He took courses in Greek and earned an M.A. in 
Classics at Penn State in 1979. He even became a candidate for a Ph.D. in Classics 
at Bryn Mawr but he did not finish that program. However Bryn Mawr published 
three of his translations of commentaries, one on Heraclitus (1984), one on 
Empedocles (1985), and one, with David Sider, on Parmenides (1986). 

,Johnstone's philosophical journey was a long search for honest responses to a 
deep philosophical question. His interest in points of view different from his own, 
and his efforts to meet the differences honestly, were apparent to all who knew 
him. Many prospective authors of articles, students and colleagues recall with 
great warmth both his encouragement and his active interchange of ideas, as edi-
tor and teacher, by correspondence or over a glass of wine. His unfailing courtesy, 
wry sense of humor, and the underlying quest for philosophical integrity enchanted 
all who knew him, as they did me more than fifty years ago. 

Note 

I However, Lewis's early work in Survey o/Symbolic Logic (1918) and Symbolic Logic (1930) 
remains influential today, reconstrued as "modal logic" fortified by Kripke and "possible world 
semantics." 



Reflections on H W. Johnstone, Jr. 9 

References 

Ayer, AJ. 1946. Language, Truth and Logic. 2nd edition. New York: Dover Publications. 

Carnap, Rudolf. 1935. Philosophy and Logical Syntax. London and New York: Kegan 
Paul. 

Carnap, Rudolf. 1947. Meaning and Necessity.' A Study in Semantics and Modal Logic. 
Chicago: University of Chicago Press. 

Johnstone. Henry W., Jr. 1954. Elementary Deductive Logic. New York: Thomas Y. 
Crowell. 

Johnstone. Henry W., Jr. 1959. Philosophy and Argument. University Park, PA: Penn-
sylvania State University Press. 

Johnstone, Henry W., Jr. (Ed. & Intro.). 1965. What is Philosophy? New York: MacMillan. 

Johnstone, Henry W., Jr. 1966. "The Relevance of Rhetoric to Philosophy and of Phi-
losophy to Rhetoric," The Quarterly Journal o/Speech, 52, pp. 41-46. Reprinted in 
Validity and Rhetoric in Philosophical Argument, pp. 39-44. 

Johnstone, Henry W., Jr. 1970. The Problem 0/ the Self University Park, PA: The 
Pennsylvania State University Press. 

Johnstone. Henry W., Jr. 1978. Validity and Rhetoric in Philosophical Argument. Uni-
versity Park, PA: The Dialogue Press of Man and the World. 

Johnstone, Henry W., Jr. and John M. Anderson. 1962. Natural Deduction: The Logical 
Basis 0/ Axiom Systems. Belmont, CA: Wadsworth. 

Johnstone, Henry W., Jr. and Maurice Natanson, (Eds.). 1965. Philosophy, Rhetoric and 
Argumentation. University Park, PA: The Pennsylvania State University Press. 

Quine, W.V.O. 1940. Mathematical Logic. Cambridge, MA: Harvard University Press. 

Salmon, Merrilee. 1989. Introduction to Logic and Critical Thinking, New York: Harcourt, 
Brace, Jovanovich. 

Sartre, Jean-Paul. 1948. Existentialism. London: Methuen & Co. 

Whately, Richard. 1838. Elements 0/ Logic. London: Longman's. 
Whitehead, A.N. and Russell, B. 1910-13. PrinCipia Mathematica. Vol. I. Cambridge: 

Cambridge University Press. 

Wittgenstein. Ludwig. 1952. Philosophical Investigations. London: The Macmillan 
Company. 

Wittgenstein, Ludwig. 1961. Tactatus Logico-Philosophicus. (1st edition, 1922.) Lon-
don: Routledge & Kegan Paul. 

Richard B. Angell 
Department o/Philosophy, Wayne State University 

Detroit, Michigan 482()2, U.SA. 
rbangell@be/latlantic.net