Syllogistic Reasoning and Canonical Reasoning

  • This is a thread to discuss the interelationships between "syllogistic reasoning" and "canonical reasoning."

    At this point the main suggestion I have for textual material is:

    1. - DeWitt's Epicurus and His Philosophy
      1. Chapter 7 - The Canon, Reason, and Nature
      2. Chapter 8 - Sensations, Anticipations, and Feelings
    2. DeWitt's "Epicurus on Immediate Presentations"
    3. 2 - DeLacy's Appendix to Philodemus' On Methods of Inference:
      1. Sources of Epicurean Empiricism
      2. Development of Epicurean Logic and Methodology
      3. Logical Controversies of Stoics, Epicureans, and Skeptics

    This page from the DeLacy material has always stuck in my memory as setting forth the issues most clearly:


    Remember that this is Delacy's opinion about Epicurus, but here is a significant part of it!

  • I will paste here a few paragraphs that appear to me to be highlights so someone skimming can decide if they want to read the whole thing:

    Important observation from the Epicurean Polystratus, that values are just as real as objects, although neither are reflections of Platonic forms, because they are real TO US:

  • I think these three pages pretty well sum up what DeLacy sees as the three categories into which Epicureans divided things (I am using DeLacy's numbering so that is why it appears out of order):

    1 - Things we can validate directly through the senses because they are nearby. (Position here should not be controversial, but contradicts Plato.)

    2 a - Things which can never be known due to our own limitations, such as whether the number of stars is odd or even - there is no test of truth for these - they can never be known.

    2 c - Things we may have to wait to validate through the senses, but ultimately we can get enough data to validate them through the senses. (Position here more aggressive but should not be controversial, still contradicts Plato.)

    2 b - Things which by nature we can never get so close as to validate by the senses (the atoms, the far reaches of space). In this category things are considered true when there is some evidence from them and no evidence to the contrary. Multiple things can be considered true / possible. Choosing from among them, that only one is true, is improper absent sufficient evidence to do so, in which case you are in category 2c rather than 2b. (Position on this category is the most controversial; contradicts Plato)

    The list of the categories:

    The test of truth for category 2a of Delacy List - Opinions about things immediately before us are validated directly against the object itself:

    The test of truth for category 2c of Delacy list - Opinions about things that can eventually be validated directly by the senses are validated when we get that information :

    The test of truth for things in category 2 b, those things which the senses can never examine closely enough to validate. This is the most challenging category and constitutes the Epicurean canonical reasoning on ultimate issues rather than syllogistic reasoning which arguably does not rely on sensory evidence.

  • Cassius

    Changed the title of the thread from “Syllogistic Reasoning vs. Canonical Reasoning” to “Syllogistic Reasoning and Canonical Reasoning”.