The Organon: Aristotle's Logic

The Method of Philosophy

  1. Texts of the Organon:

    Note: 'Organon' is Latin for "instrument"

    1. Categories - Aristotle on Substance

    2. On Interpretation - The parts of, and types of, propositions

    3. Prior Analytics - The general theory of deductive inference

    4. Posterior Analytics - The nature of demonstrative reasoning and definition

    5. Topics - The problems inherent in dialectical reasoning

    6. On Sophistical Refutations - The nature of fallacious reasoning

  2. The Purpose of the Organon:

    1. To discover and explicate the forms of reason common to all sciences

      1. Theoretical

      2. Practical

      3. Popular -

        1. Rhetorical

        2. Sophistical

    2. To give instruction in the efficient forms of argument and reason

  3. The Categories: "What is it that is?"

    Note: 'kategoria' means "statement of charge," or "assertion," or "predication"

    1. The Use of Names -

      1. Homonyms - same name, different definition

      2. Synonyms - same name, same definition

      3. Paronyms - names derived from a predicate

    2. Three kinds of "things" ('onta') -

      1. That which is said "of" something - "Socrates is a man."

      2. That which is said to "be in" something - "Socrates is white."

        Note: There is a special category of things which can be both said "of" and "in" a subject - "Socrates is knowledgeable of grammar."

      3. That which is neither said "of" nor "in" something - "Socrates"

    3. Two Kinds of Substance -

      1. Primary Substance - That which is neither said "of" nor "in"

        1. The cause of all secondary substance (contra Plato)

        2. All primary substances are equal

        3. Only primary substance signifies a real thing (a "this")

        4. Primary substances are neither more nor less

        5. Primary substances allow contrary properties (because of change)

      2. Secondary Substance - The species of a primary substance

  4. On Interpretation: The Square of Opposition

    1. The Components of language -

      1. Words - symbols of ideas in the mind (spoken or written)

        1. Nouns ("names") - conventional symbols for things

        2. Verbs - temporal symbols of predicates (that which is said "of")

      2. Sentences - a meaningful compound of symbols (some of the symbols [i.
      3. , nouns] being independently meaningful)

      4. Proposition - a sentence which has a truth-value

    2. The Four kinds of Propositions -

      1. Universal Affirmative (A)

      2. Universal Negative (E)

      3. Particular Affirmative (I)

      4. Particular Negative (O)

    3. The Logical Relationships between the four propositions -

      1. Contrary opposites

      2. Contradictory opposites

      3. Subcontraries

      4. Subalterns

      Note: The four categorical propositions along with their four relations creates the "Square of Opposition."

    4. Other Derivative Logical Relations -

      1. The Law of non-contradiction (18a35)

      2. The necessity/contingency distinction (19a20ff)

  5. The Posterior Analytics: Deductive and Inductive Reasoning

    1. Scientific Knowledge ('episteme') - understanding the necessary cause of an event (a "thing")

    2. Two Forms of Dialectical Reasoning - The Method of Scientific Knowledge

      1. Syllogism - From Universal to Particular propositions

      2. Induction - From Particular to Universal propositions

    3. Universal Categorical propositions are derived from sensory experience

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