The Logic of William of Ockham

335 Pages·1935·33.333 MB·English

by  Ernest Addison Moody

THE LOGIC
OF WILLIAM OF OCKHAM
by
ERNEST ADDISON MOODY
Submitted in partial fulfillment of the
requirements for the degree of Doctor of
Philosophy, in the Faculty of Philosophy,
Columbia University.
NEW YORK
SHEED & WARD, INC.
MCMXXXV

PREFACE
AT a time when medireval philosophy is rece1vmg more
serious attention than for some hundreds of years, no apologies
need be offered for undertaking a detailed first hand study
of Ockham's logic. His reputation, as the foremost of the
nominalists and as the medireval philosopher whose thought
was in many respects responsible for fundamental and
characteristic attitudes and methods in modern science,
exhibits him as the most significant philosopher of the later
Middle Ages.
Despite Ockham's fame, and the admitted importance of
his nominalistic restatement of the Organon, no modern
exposition of his logic, with any pretence at thoroughness or
close analysis, exists. Furthermore, texts of Ockham's philo
sophical writings are extremely scarce, so that it is not easy
for those who wish to acquire a clear and adequate under
standing of Ockham's thought, to do so. The present study
is designed to reveal, through a careful analysis carried out
with adequate source material, the philosophical content,
and the essentially aristotelian inspiration, of Ockham's
theory of science.
In addition to this purely historical interest, a twentieth
century re-reading of Ockham's logical discussions has direct
interest from the philosophical point of view. One cannot
for long study his discussions of quantity, quality, time, place,
V
PREFACE
and relation, without being struck by the relevance of his
analyses of logical and physical problems to the speculative
interests of contemporary science. Though Ockham's language,
and the aristotelian background of his thought, are largely
absent from current statements of scientific problems, his
interests are surprisingly "modern," and remarkably free
from the theological preoccupations which, in the case of
most medireval philosophical writings, obscure their scientific
content to modern secular readers. The direct philosophical
interest, for our own times, of Ockham's discussions, is
heightened by the fact that he not only deals with problems
that seem pertinent to us, but offers analyses of these problems,
and modes of solution, which possess great philosophic power
-though they are for the most part unfamiliar to contemporary
philosophers of science.
The reader's indulgence is asked for the unavoidable
difficulties attendant on the attempt to render Ockham's
thought accurately, in a language which to him would have
seemed almost hopelessly diffuse and equivocal. The
niceties of rhetoric have been sacrificed to what seemed
a more important end-namely, to get to the bottom of
Ockham's discussions, as far as possible, and to reveal,
even at the cost of unusual terminology and seemingly
needless restatement, what Ockham's much heralded
"nominalism" is.
My indebtedness to Dr. Richard McKeon, for his aid in
the task of elucidating Ockham's thought within the context
of Greek and medireval tradition, and for his kindness in
lending me his much prized photostatic copies of Ockham's
writings, is hereby acknowledged wft h the utmost gratitude.
J.
I am also much indebted to Professor F. E. Wood
bridge, of Columbia University, for many illuminating ideas
PREFACE vii
communicated with rare felicity in the course of his
discussions of philosophical empiricism. And for her immense
patience, sympathy, and encouragement, without which
this book could not have been :finished, I thank my
wife.
E.A.M.
Greenwich, Conn.
Sept., 1935.

TABLE OF CONTENTS
PAGE
PREFACE . v
CHAPTER ONE
OCKHAM AND THE SCHOLASTIC TRADITION r
I. The "place" assigned to Ockham in historical studies of medireval
philosophy-as innovator, sceptic, "subjectiVISt," and destructive
critic of scholastic aristotelianism. Doubts concerning this estimate
-Ockham's opposition to the moderni, his constant appeal to
Aristotle against them. An alternative hypotheslS of historical
orientation-Ockham as critic of neo-platomst, arab, and augus
tinian corruptions of Aristotle.
II. Mediaeval interest in logic not merely pedagogic, but philosophical.
Scholast1cism as a single organic philosophy vs. scholasticism as a
conflict of philosophies. St. Thomas' critique of averroism and
augustinism; Duns Scotus' critique of Aquinas. Ockham's "nomin
al1Sm" originates in his statement of logic, and in his analysis of the
term "universal." Porphyry's questions and his fifth predicable
the "problem of individuation" and the "sixth predicable."
Ockham, like Aquinas, a critic of the logical realism of the augus
tinian and arab traditions, revived after Aquinas by the scotists.
III. Ockham's life and writings. Authors cited and positions criticized
by him. The terminist logic-Petrus Hispanus vs. Michael Psellos
as author of the Summulae logicales.
IV. Problems of aim ~nd method involved in the study of Ockham's
logic and of hlS "nominalism." Historical vs. philosophical
approach; synthetic vs. analytic methods of study. Judgments of
comparison, and historical estimates, of little value unless preceded
by detailed analysis from the philosophical point of view. Aim of
present study: to make clear, in Ockham's own terms and in contrast
to alternative "aristotelianisms" which he opposed and criticized,
what Ockham's interpretation of aristotelian logic was. We cannot
judge Ockham's aristotelianism by the "real Aristotle," but only
by our own, or by some other, interpretation of Aristotle.
ix
CONTENTS
X
CHAPTER TWO
PAGE
THE LOGIC OF TERMS 31
I. The nature of logic-scientia rationalis and scientia realis. Logic not
a speculative science, but an art. It treats of human "fabrications"
-not of creations, either divine or hum.an. The "real distinction"
pre-supposed by logic is that which is involved in all science of
nature-namely, between substances and the qualitative contraries.
II. The term-its definition. Natural and conventional signs. Sigmfica
tive and non-significative supposition of terms. Terms of first and
of second intention-the transcendental terms of metaphysics.
Theories as to the ontological status of the concept or intention
primacy, for Ockham, of intelligence and the intelligible. Ockham's
logical nominalism a consequence of his metaphysical realism.
III. Principles of incomplex signification. Absolute vs. connotative terms.
Concrete vs. abstract terms; does the term "humanity" signify
anything other than the individuals signified by the term "man?"
Ockham's answer, and that of Avicenna and Duns Scotus.
CHAPTER THREE
PORPHYRY AND THE PROBLEM OF UNIVERSALS 66
I. Porphyry's reversal of the aristotelian order of priority between
signification and predication, meamng and truth, things and facts.
Porphyry's neo-platonist metaphysics constantly present in his
treatise on the predicables, though concealed by equivocal language.
Ockham's commentary on Porphyry expressed as an "interpreta
tion," though actually equivalent to a radical criticism of the
porphyrian viewpoint.
II. The problem of universals and of individuation. Ockham's analysis
of the meanings of the terms "universal" and "individual."
Analysis of the expression "universale in re," in terms of the distinc
tion between natural and conventional signs. Aquinas vs. Averroes
-are human beings intelligent by nature, or only by illumination
from a superior Intelligence? Avicenna 's compromise, and its
influence on Duns Scotus. Ockham's criticism of the scotist notions
of natura indeterminataa nd of the distinctiofo rmalzs a parte rei. Ockham's
answers to Porphyry's three questions.
III. Treatment of the predicables, by Ockham, as terms of second inten
tion; his fidelity to Aristotle's treatment of them in the Topics.
Constant correction of Porphyry's equivocation. Genus and species;
differentia; property; accident.
IV. Other terms of second intention. Meanings of the terms "definition,"
"description," "subject," "predicate," "signify," "opposite,"
and "attribute."
CONTENTS.
Xl
CHAPTER FOUR
PAGE
THE CATEGORIES OF ARISTOTLE II8
I. The Categoriesn ot a metaphysical treatise, but concerned with the
terms of first intention used in the science of nature and in mathe
matics. Relation of metaphysics to discursive sciences-metaphysics
not a demonstrative nor discursive science. Equivocal predicatictn
of ens of the terms in the categories-due to abstractive character
of all incomplex signification. Distinction between substances and
the contraries, or between thmgs and facts, primary for all discur
sive science, though not for first philosophy. Distinction between
ensp er se and ens per aliud, or between ms in actu and ens in potentia,
not metaphysically primary, but involved only in the analysis ot
motion and in the sciences of changeable things. Univocal,
equivocal, and denominative terms. "Predicable of a subject"
and "present in a subject." Ockham vs. Boethius. The dictum dB
omni of the Categories.T he categorical order a logical, and not meta
physical, order. Ockham's method and interests, in his analysis of
modes of signification.
II. The category of substance. First and second substances. Qpale
gui,da nd hoe aliquid. Characteristics of substantive terms.
III. The category of quantity. Quantity not a "thing" distinct in being
from substances and qualities. Critique of the motkrni. What are
mathematical propositions true of? Meanings of the word "part"
-things numbered are only metaphorically "parts" of the number.
Class names, and numbers as classes of classes. Quantitative terms
signify nothing other than substances or qualities-but they signify
them, or their parts, coniunctimo, r else through connoting the opera
tions of numbering or of dividing. Ockham's analysis of quantity
based on the aristotelian principle that the actually infinite is not a
principle of human knowledge; the scotist view involves a departure
from this aristotelian principle.
IV. The category of relation. Relations not "things," but ways of
signifying substances or qualities, either connotatively or "taken
together" (coniunctim). Is the word "relative" a term of second
intention? Difference in mode of signification between concrete
and abstract forms of relative terms-e.g., "father" and "father
hood." D1Stinctive logical characteristics of relative terms.
V. The category of quality. Four kinds of qualitative terms. "Real"
qualities-the contraries which are principles of change and of
sense perception. Real quahties signified coniunctimb y qualitative
terms of the second species. The third and fourth kinds of qualitative
terms. Contrariety, variation in degree, "like" and "unlike."
Time and place, and the remaining c.ategories, Sigruficance
of Ockham's analysis.
:xii CONTENTS
CHAPTER FIVE
PAGE
FORMS OF COMPLEX SIGNIFICATION 176
I. Complex llS. incomplex signification; apprehension and judgment.
The mode of signification of the terms "true" and "false." The
formal character of Ockham's analysis of the proposition.
II. Ockham's exposition of the De interpretationaen,d his analysis of the
proposition in his Summat otiusl ogicae.T he aims and methods of the
termioist logicians. Ockham's use of the distinction between
signifaatioa nd suppositw-the kinds of suppositiop ersonali,sD. ivision
of propositional forms. The categorical proposition-ingular,
particular, and universal. Time reference of verb or copula. Future
contingents-the scientific and the theological answer. Modal
propositions-sensus dwisusa nd sensusc ompositusE. xponible proposi
tions-are all categorical propositions, whose terms stand for
individual existent things, equivalent to hypothetical or conditional
propositions? The possibility of necessary categorical propositions,
in the real sciences, shown to presuppose Ockham's "nominalistic"
solution of the problem of universals.
III. The categorical syllogism-its kinds. Difference between demonstra
tive and probable premises. The syllogism as a form of complex
signification. Its modes and figures-can their vahd1ty be proved?
The dictum de omm of the Prior Anarytics. Expository syllogisms;
Ockham's detailed analysis of modal syllogisms.
CHAPTER SIX
DEMONSTRATION AND DEFINITION
220
I. The demonstrative syllogism-its definition, and connotation of
"evident knowledge." Epistemic conditions of demonstration
extrinsic principles. Characteristics of propositions entering into
demonstrations: necessity, universality. The two kinds of per se
propositions; the attribute and its "first subject."
II. Evident knowledge which is non-demonstrative. Experience,
involving both sense perception and mtellectual recognition, is the
.sineq uan ono f our grasp of scientific principles. Intellectual appre
hension of the undivided and of the indivisible.
Universal propositions-demonstrable and indemonstrable.
Meanings of "prior," "posterior," "principle." Prionty of things
or of indwiduan1a tureso, ver facts or euents. Knowledge of the fact vs.
knowledge of the reasoned fact; a posterioprir oof, and its conditions.
Subalternant and subalternate sciences-natural philosophy not
subalternate to metaphysics or logic, nor llicev ersa.