Logical Works

• In the Late Ancient curriculum many students would start with logic and never progress beyond their study of logic.
• For many hundreds of years logic meant Aristotle since he is the first person to give a systematic account of argumentation.
• Logic is at the heart of Aristotle's goal of understanding the natural world.

The Organon (Tool)

• Categories
• On Interpretation
• Prior Analytics
• Posterior Analytics
• Topics
• On Sophistical Refutations

Categories

• What are the properties of things in the world?
• Aristotle identifies ten kinds of property that a thing can have.

Categories (cont'd)

Categories (cont'd)

• Essential properties vs. accidental properties.
• Universals vs. particulars.

Categories (cont'd)

• Contradiction
• All, Some, & None

On Interpretation

• How can words (predicates, categories) be combined into statements?
• Not all combinations will be valid statements.
• Premise & conclusion.

Prior Analytics

• Which kinds of valid statements can be combined to form valid arguments?
• Not all combinations will be valid arguments.

Prior Analytics (cont'd)

• Conjunctions
• Syllogisms (using variables!)
• "X results of necessity from Y and Z if it would be impossible for X to be false when Y and Z are true." (SEP)

Topics & Sophistical Refutations

• Not really works of logic.
• Traditionally included within the Organon probably because they did not fit anywhere else within Aristotle's works.
• Philosophy vs. Sophistry.

Epistemology

• ἐπιστήμη - knowledge, understanding
• True belief (doxa) vs. knowledge (episteme)

Posterior Analytics

• How does Aristotle define knowledge / understanding?
• What kinds of valid arguments are useful for discovering knowledge?

Posterior Analytics (cont'd)

• In Aristotle's epistemology an argument can be guaranteed to yield understanding if we can demonstrate *why* something behaves the way it does.
• Chain of syllogisms, a demonstration.

Posterior Analytics (cont'd)

• Where does the chain of syllogisms end?
• There is an infinite regress here. Each premise is some other deduction's conclusion.
• Aristotle stops the chain at "first principles".

Posterior Analytics (cont'd)

• Aristotle is a "foundationalist".
• He leaves himself open to skeptical attack by arbitrarily stopping at "first principles".
• Contrasts sharply with Plato's theory of recollection.