Aristotle's Organon

Aristotle was a Greek philosopher and scientist, a pupil of Plato, and teacher of Alexander the Great. The Organon (Instrument) refers to a collection of six of Aristotle's work in logic: Categories, Prior Analytics, De Interpretatione, Posterior Analytics, Sophistical Refutations, and Topics. Andronicus of Rhodes (c. 428-348 B.C.) determined the ordering of the six works around 40 B.C. Although Plato (c. 428-348 B.C.) and Socrates (c. 470-399 B.C.) delved into logical themes, Aristotle actually systematized the study of logic, which dominated scientific reasoning in the Western world for 2,000 years.
The goal of Organon is not to tell readers what it is true, but rather to give approaches to how to investigate the truth and how to make sense of the world. The primary tool in Aristotle's tool kit is the syllogism, a three-step argument, such as "All women are mortal; Cleopatra is a woman; therefore, Cleopatra is mortal." If the two premises are true, we know that the conclusion must be true. Aristotle also made a distinction between particulars and universals (general categories). Cleopatra is a particular term. Woman and mortal are universal terms. When universal are used, they are preceded by "all", "some", or "no." Aristotle analyzed many possible kinds of syllogisms and showed which of them are valid.
Aristotle also extended his analysis to syllogisms that involved modal logic - that is, statements containing words "possibly" or "necessarily." Modern mathematical logic can depart from Aristotle's methodologies or extend his work into other kinds of sentences structures, including ones that express more complex relationships or ones that involve more than one quantifier, such as "No women like all women who dislike some women." Nevertheless, Aristotle's systematic attempt at developing logic is considered to be one of humankind's greatest achievements, providing an early impetus for fields of mathematics that are close in partnership with logic and even influencing theologians in their quest to understand reality.