[4.18.7] William Ockham on Supposition and Sciences

William Ockham (1285-1349 AD), in the treatise Commentary on the Sentences of Peter Lombard writes about the relationship between types of supposition and types of sciences:

  • Propositions (sentences) are made up of terms.
  • Terms in a proposition refer to other terms – the suppositum (or supposita); this relation is called supposition. The supposition of a term always occurs in a propositional context and can be entirely different from its signification (see [4.0.1]).
  • The relation between the term and the suppositum in the propositional context is called supposition (reference).
  • Ockham defines three kinds of supposition: personal, simple, and material.
  • For Ockham, science is a collection of true propositions. These propositions shouldn’t exclusively be about (1.3.10) universal knowledge.
  • “Traditionally, there were three kinds of sciences people distinguished: (a) the so called ‘real’ sciences: physics, metaphysics, and mathematics; (b) the so called ‘rational’ science: logic; and (c) ‘grammatical’ science: grammar.” (Spade)
  • Real science has personal supposition; rational science has simple supposition; grammatical science has material supposition.

The following OntoUML diagram presents Ockhams’s model of the relation between supposition and sciences:

William Ockham on Supposition and Sciences
ClassDescriptionRelations
Propositionproposition or sentence is made up of terms.component of Science
TermA mental, spoken, or written term.component of Proposition; supposits for Suppositum
SuppositumSuppositum is “whatever a term supposits for’ or refers to.”role of Term
Supposition“What sort of relation is supposition? Well, the first thing we can say about it is that supposition is a semantic relation. To a first (but pretty good) approximation, supposition in this first part of the theory is what nowadays we call ‘reference.’ It is the relation between the terms used in a proposition and the things those terms are used to talk about in that proposition. […]
supposition occurs only in a propositional context. And this is the first main difference between supposition and signification, which can occur outside a propositional context according to almost any author.
The second main difference is this: We do not always in practice use terms in propositions to talk about what those terms signify. We use them in a variety of other ways too. Hence supposition also differs from signification insofar as a term may signify one thing, but supposit on a given occasion for something entirely different.” (Spade – History of the Problem of Universals in the Middle Ages)
relates Proposition; Supposition; Suppositum
PersonalSupposition“Going with the ‘real’ sciences, there is what is called ‘personal’ supposition (which has nothing especially to do with persons — although it perhaps originated in theorizing about the persons of the Trinity). There terms stand for the things they signify. For example, in the sentence ‘Man is an animal’, the subject term ‘man’ is in personal supposition, and stands for individual human beings. They are the ones who are animals. The spoken or written word is not an
animal, and neither is the concept.” (Spade)
subkind of Supposition
SimpleSupposition“Going with the ‘rational’ science of logic, there is what is called “simple” supposition. There terms stand for concepts they do not signify. These concepts are the genera and species that logic talks about. For instance, in the sentence ‘Man is a species’ (in the sense in which it is true), the subject term ‘man’ stands for the concept “man,” which is a species — that is, a species-concept. It definitely does not
stand for any real universal man.” (Spade)
subkind of Supposition
MaterialSupposition“Going with ‘grammatical’ science, there is what is called ‘material’ supposition, in which terms stand for words they do not signify. For example, in ‘Man has three letters’, the subject term ‘man’ is in material supposition — at least in the sense in which the sentence is true. (But don’t make the mistake of thinking that Ockham’s “material supposition” is just what we do with quotation marks. It is more
complex than that.)” (Spade)
subkind of Supposition
ScienceFor Ockham, the object of a science is simply sentences with general terms in them. That’s how he accommodates Aristotle’s dictum that science deals with the universal.
This of course doesn’t mean that we can never, in our knowledge, get beyond the level of language to things. For Ockham, there are two senses of the term ‘know’ (= scire in Latin, from which comes scientia = science”):
(a) As we just said, the sense in which to know is to know a sentence, or a term in that sentence. In this sense, the object of a science is universal.
(b) We can also be said to know what that sentence is about, what the subject-term in it stands or supposits for. What we know in this sense is invariably the individual, metaphysically speaking, since there is nothing else for Ockham. This is not the object of science in the sense Aristotle is talking about. […]
Traditionally, there were three kinds of sciences people distinguished: (a) the so called ‘real’ sciences: physics, metaphysics and mathematics; (b) the so called ‘rational’ science: logic; and (c) ‘grammatical’ science: grammar. For each of these kinds of science, Ockham distinguishes a kind of ‘supposition.’” (Spade)
RealScience; “Traditionally, there were three kinds of sciences people distinguished: (a) the so called ‘real’ sciences: physics, metaphysics and mathematics” (Spade)subkind of Science; has PersonalSupposition
RationalScience; “Traditionally, there were three kinds of sciences people distinguished: (b) the so called ‘rational’ science: logic” (Spade)subkind of Science; has SimpleSupposition
GrammaticalScience“Traditionally, there were three kinds of sciences people distinguished: (c) ‘grammatical’ science: grammar. For each of these kinds of science, Ockham distinguishes a kind of ‘supposition.’” (Spade)subkind of Science; has MaterialSupposition

Sources

First published: 9/12/2021

[4.17.1] John Buridan on Logic as a Science

John Buridan (Jean Buridan 1301-1358) in Quaestiones in Porphyrii Isagogen and Summulae de Dialectica writes about the place of logic in the realm of sciences:

  • Science in a broader sense has theoretical and practical subjects (see also Aristotle’s categorization [1.3.10]).
  • Buridan sustains that – contrary to other contemporary opinions – logic is not the “science of sciences” because metaphysics fulfills this role: “Indeed, logic should not even be called the science of sciences, for this would indicate a certain excellence of logic with respect to [all] other sciences, which it cannot have with respect to metaphysics; in fact, metaphysics, rather than logic, should more truly be called the science of sciences, having access to the principles of all inquiries.”
  • Buridan divides logic into logic-in-use (logica utens), containing logical rules used in daily reasoning and logical doctrine (logical docens) preoccupied with universal and necessary laws of reasoning. The laws of reasoning spell out the logical rules.
  • Logical doctrine is a practical science, while logic-in-use is not a science.

The following OntoUML diagram shows the logic’s place in the hierarchy of science according to Buridan:

Buridan on logic and science
ClassDescriptionRelations
ScienceScience in a broader sense applies to theoretical and practical subjects.
ScienceInStrictSense“In his questions on Porphyry’s Isagoge, Buridan […] distinguishes between ‘science’ in the strict sense, in which it applies only to a body of necessary, universal, theoretical knowledge, consisting of the conclusions of scientific demonstrations in the strict Aristotelian sense, from ‘science’ in a broader sense.”subkind of Science
PracticalScience“In the latter sense, the term applies not only to strictly theoretical but also to practical subjects, namely, subjects concerning things that are within our power to make or do (or to refrain from making or doing), and the knowledge of which is useful for achieving our ends in these activities. In this broader sense, the art of logic also deserves to be called a science, namely, a practical science, the possession of which guides us in our rational practice of forming and evaluating arguments.”subkind of Science
LogicLogic is in its entirety about arguments, their principles, parts, and attributes; therefore, we should consider in logic everything in its relation to argumentation. Thus, the division of logic is taken from argumentation. […]
In this broader sense, the art of logic also deserves to be called a science, namely, a practical science, the possession of which guides us in our rational practice of forming and evaluating arguments. In this connection, Buridan also draws the famous distinction between logica utens and logica docens, that is, logic-in-use and logical doctrine.”
generalizes Logic-in-use and LogicalDoctrine
Logic-in-use“Buridan also draws the famous distinction between logica utens and logica docens, that is, logic-in-use and logical doctrine, only the latter of which can be called an art or practical science, whereas the former embodies those operative principles that are spelled out by the latter. For of course logical rules are operative in all our rational activities, yet those rules in operation, without being spelled out and reflected on, do not constitute logical knowledge. In fact, as Buridan remarks, sometimes, as in the case of sophistic arguments, they lead to something contrary to knowledge, namely, deception.”
LogicalRule logical rules are operative in all our rational activities” exclusive part of Logic-in-use
LogicalDoctrine “Buridan also draws the famous distinction between logica utens and logica docens, that is, logic-in-use and logical doctrine, only the latter of which can be called an art or practical science, whereas the former embodies those operative principles that are spelled out by the latter. […] logical doctrine, the systematic body of knowledge concerning the universal, necessary laws of various forms of reasoning, is certainly a science, even if not a theoretical one, such as metaphysics, mathematics, or physics. It is, rather, a practical science, which teaches us how to construct and evaluate our argumentations to achieve our desired ends with them, whatever those ends may be.”
LawOfReasoningLaws of reasoning are universal, necessary laws describing, spelling out the practical logical rules.spells out LogicalRule; component of LogicalDoctrine

Sources:

  • All citations from: Klima, Gyula, “John Buridan”, Oxford University Press, 2009
  • Zupko, Jack, “John Buridan“, The Stanford Encyclopedia of Philosophy (Fall 2018 Edition), Edward N. Zalta (ed.)

First published: 1/8/2021