[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; exclusive part 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

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