The Organon consists of the following works:
- Categories (text) , where Aristotle introduced his 10-fold classification of that which exists;
- De Interpretatione (On Interpretation), which provides Aristotle's principle contribution to philosophy of language;
- Prior Analytics, where Aristotle introduces his syllogistic method, also known as term logic;
- Posterior Analytics (text) where he discusses his syllogistic system, and why it is correct;
- Topics (text) , where he treats issues in constructing valid arguments; and
- On Sophistical Refutations (text) treats logical fallacies.
The order of the works is not chronological (which is now hard to determine), but systematic. Aristotle's Metaphysics has many points of intellectual overlap with the works making up the Organon, but is not traditionally considered part of it.
These works have been used in the school Lyceum lead by Aristotle for learning or teaching, and some parts of them seem to be a scheme of a lecture on logic. So much so that after Aristotle's death, his publishers (e.g. Andronicus of Rhodes in 50 BC) collected these works and may have even attributed some affixes from Theophrastus or Eudemos (e.g. the 10.-15. chapters of Categories are maybe written by Theophrastus) to him.
Scientific relevancy of Organon is so great: in that we can find the first ontological category theory (relevant in some branches of intensional logic ), the first development of formal logic, the first known serious scientific inquisitions on the theory of (formal and informal) reasoning, the foundations of modal logic, and some antecedents of methodology of sciences.
- A summary of the Organon by James Evans