The First Doctrines of Logic were a set of principles pertaining to Vulcan logic.

After Spock's mind became disordered due to experiencing time as a fluid, he started maniaclly reciting the First Doctrines of Logic as he tried in vain to ground himself and interpret the experience using conventional logic. (DIS: "Light and Shadows", "If Memory Serves")

Excerpts

• "Constructionism combines the epistemological thesis about what can be known with a meta-philosophical view on the nature of philosophical questions."
• "Formal logic utilizes plausible reasoning and inductive methods organized into subsystems."
• "The most important of these systems is classical logic."
• "Formal logic utilizes plausible..."
• "But even if their premises are true..."
• "All inductive arguments are therefore deductively invalid."
• "The premises of an inductive argument do not entail the truth of the argument's conclusion."
• "In deductive logic, the methods of reasoning and the procedure for finding evidence are investigated."
• "Only if it is impossible for the conclusion to be false while the premises are all true."
• "To say that a logical construction is valid is to say that the premises are true."
• "A deductive argument is one that aims to show its conclusion must be true."