Aristotle: Knowledge, Science, and Logical Syllogisms

Posted on May 7, 2025 in Philosophy and ethics

Degrees of Knowledge in Aristotelian Philosophy

Levels of Knowing

Aristotle identified several degrees or levels of knowledge:

  • Sensation (Aisthesis): Knowledge gained through the senses. It is essential, as all knowledge begins with the senses.
  • Memory (Mneme): The preservation of sensation; learning is based on this.
  • Experience (Empeiria): Arises from repeated memories of the same thing. It is characteristic of experts. It does not transcend sensible things and responds to what something is, but not why.
  • Art (Techne): Knowledge derived from experience; it is the artist’s or craftsman’s knowledge. It goes beyond particular things, is capable of grasping universal concepts, and can explain why something is the case.
  • Technical Skill: Described as a recombination of experience, memory, and sensation (corrected from “feelings”).
  • Science (Episteme): A more perfect knowledge than art (Techne), as it is based on universal concepts and understanding of first causes and principles. It is not primarily for the manufacture of objects. Science seeks the first causes and principles from which other things are known. It is knowledge of causes—necessary, universal, and therefore, true.

Specialized Knowledge: The Domain of Science

Science, as specialized knowledge, answers three fundamental questions:

  • That something is (its existence)
  • What it is (its essence)
  • Why it is (its cause)

Key Scientific Procedures

Science employs two primary procedures:

  • Definition: States what a thing is by determining the genus or class to which it belongs and its specific difference (i.e., what distinguishes it from other things, its essence).
  • Demonstration: Answers questions of existence and causes. This is achieved through the “scientific syllogism.” The first principles of science, upon which demonstrations are built, are themselves indemonstrable, evident, and primary. These principles are of two types:
    1. Axioms: Common principles accepted in all sciences.
    2. Theses: Particular principles specific to a science, which include:
      • Assumptions (Hypotheses): Assertions of the existence of the subject matter.
      • Definitions: Statements of the essence of attributes.

Classification of Sciences

Aristotle divided sciences into three categories:

  • Theoretical Sciences: Seek knowledge for its own sake.
    • Physics: Study of material and mobile beings.
    • Mathematics: Study of material (by abstraction) and immobile beings.
    • Metaphysics (First Philosophy): Study of immaterial and immobile beings (being qua being).
  • Practical Sciences: Aim to regulate human behavior.
    • Ethics
    • Politics
  • Poietic (Productive) Sciences: Aim at the production of artificial objects or performances.
    • Rhetoric
    • Poetics
    • Dialectics
    • Medicine
    • Music

Logic serves as an essential tool or introduction (propaedeutic) to all sciences.

Aristotle’s Logic: The Organon and Syllogism

Aristotle is considered the true creator of the systematic study of logic.

The Organon: Foundational Logical Works

His logical works are collectively known as the Organon (“instrument” or “tool”). The source text highlights the following components or books from it:

  • On the Categories (Categoriae)
  • “First analytical sophistry” (This likely refers to Aristotle’s Prior Analytics, which covers the syllogism, and Sophistical Refutations, which deals with fallacies.)
  • Posterior Analytics (Analytica Posteriora)

The Aristotelian Syllogism

A core part of Aristotle’s logic, detailed especially in the Prior Analytics (related to what the source terms “First analytical sophistry”), is the syllogism. The Prior Analytics is dedicated to the scientific syllogism.

Aristotle’s syllogism is a form of deductive reasoning. Based on true principles or premises, it can lead to a conclusion that is also necessarily true. While there are several forms (figures and moods), the structure of a perfect syllogism (typically the first figure, AAA mood, known as “Barbara”) is often exemplified as follows:

Structure of a Perfect Syllogism (Example)

  • Major Premise: All B is A.
  • Minor Premise: All C is B.
  • Conclusion: Therefore, all C is A.

Types of Propositions

Syllogisms are constructed from propositions, which can be classified in four ways based on quality (affirmative/negative) and quantity (universal/particular; the source’s “private” is corrected to “particular”):

  • Universal Affirmative (A): e.g., All S is P.
  • Universal Negative (E): e.g., No S is P.
  • Particular Affirmative (I): e.g., Some S is P.
  • Particular Negative (O): e.g., Some S is not P.

Fundamental Principles of the Syllogism

The validity of syllogisms rests on fundamental logical principles. The source indicates four points, which can be understood in relation to the Dictum de Omni and Dictum de Nullo:

  1. Principle of Convenience (or Agreement)
  2. Principle of Discrepancy (or Disagreement)
  3. Principle of “All of the Above” (referring to Dictum de Omni: What is affirmed of an entire class may be affirmed of any member of that class.)
  4. Principle of “None of That” (referring to Dictum de Nullo: What is denied of an entire class may be denied of any member of that class.)

Rules for a Valid Syllogism

For a syllogism to be valid, it must adhere to several rules:

  1. Three Terms: The syllogism must have exactly three terms: the major term, the minor term, and the middle term. Each term must be used consistently in the same sense.
  2. Scope of Terms in Conclusion: No term can have a wider scope (be distributed) in the conclusion than it had in the premises.
  3. Middle Term Exclusion: The middle term must not appear in the conclusion.
  4. Distribution of Middle Term: The middle term must be distributed (refer to all members of its class) in at least one premise.
  5. Two Negative Premises: From two negative premises, no conclusion follows.
  6. Affirmative Premises, Negative Conclusion: If both premises are affirmative, the conclusion must be affirmative. (A negative conclusion cannot follow from two affirmative premises).
  7. Two Particular Premises: From two particular premises, no conclusion follows.
  8. Conclusion Follows Weaker Part: The conclusion always follows the “weaker” part:
    • If one premise is particular, the conclusion must be particular.
    • If one premise is negative, the conclusion must be negative.