1. [Greek: Kataegoriai]: _Categoriae_: On simple expressions
signifying different kinds of things and capable of predication
[probably an early work of Aristotle, accepting species and genera as
"secondary substances" in deference to Plato's teaching].
2. [Greek: peri Hermaeneias]: _De interpretatione_: On language as
expression of mind, and especially on the enunciation or assertion
([Greek: apophansis, apophantikos logos]) [rejected by Andronicus
according to Alexander; but probably an early work of Aristotle, based
on Plato's analysis of the sentence into noun and verb].
3. [Greek: Analytika protera]: _Analytica Priora_, On syllogism, with
a view to demonstration.
4. [Greek: Analytika ustera]: _Analytica Posteriora_: On
demonstration, or demonstrative or scientific syllogism ([Greek:
apodeixis, apodeiktikos ae epistaemonilos syllogismos]).
5. [Greek: Topika]: _Topica_: On dialectical syllogism ([Greek:
Dialektikos syllogismos]), so called from consisting mainly of
commonplaces ([Greek: topoi]. _loci_), or general sources of argument.
6. [Greek: Sophistikoi elenchoi]: _Sophistici Elenchi_: On sophistic
([Greek: sophistikos]) or eristic syllogism ([Greek: eristikos
syllogismos]), so called from the fallacies used by sophists in
refutation ([Greek: elenchos]) of their opponents.
[Numbers 1-6 were afterwards grouped together as the _Organon_.]