memory alpha
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide."
- T'Plana-Hath, Matron of Vulcan philosophy

Logic was the study of the principles of reasoning. As a form of science, logic was used to solve various problems through the application of deductive reasoning. The absence of logic was known as illogic.

Vulcans adopted logic as their way of life, a life of order and control through logic. (ENT: "The Andorian Incident") Surak introduced the principles of logic to his people in the hope of stopping the destructive wars which plagued Vulcan. His hope was that by embracing logic above Emotion, the Vulcan people could reign in the savagery of their emotions and create an ordered society. Some basic principles of Vulcan logic were laid out in the First Doctrines of Logic. (DIS: "Light and Shadows")

Although the Vulcan majority lived by logic, there were some who tried to balance their emotions and logic; they were better known as V'tosh ka'tur, Vulcans without logic. (TOS: "The Savage Curtain"; TNG: "Gambit, Part II"; ENT: "Fusion") There were also Vulcans, like Sybok, who rejected logic outright and embraced emotion. (Star Trek V: The Final Frontier)

Other Vulcans chose instead to further develop their mental discipline through the Kolinahr ritual to the point of purging all vestigial emotions and living solely by pure logic. This process could involve years of intense study and meditation. (Star Trek: The Motion Picture; VOY: "Flashback", "Gravity", "Fury")

Several machine-based lifeforms strictly followed logic as well:

See also

Appendices

References to logic

"Your illogical approach to chess does have its advantages on occasion, captain."
- Spock, to Kirk
In the final draft script of "Charlie X", Spock instead described Kirk's approach to chess as "eccentric."
"You cannot succeed, commodore. Your only logical alternative is to return to the ship."
- Spock, to Commodore Matt Decker
It is debatable whether Vulcan usage of the word "logic" is consistent with the real-world concept of logic. This question has never been discussed on-screen or in canon sources.

External links