Deductive reasoning and the argument is “valid”, it is possible for the conclusion to be false (determined to be false with a counterexample or other means). Aristotle started documenting deductive reasoning in the 4th century BC. Deductive reasoning Deductive reasoning, also deductive logic, logical deduction is the process of reasoning from one or more statements (premises) to reach a logically certain conclusion. Deductive reasoning goes in the same direction as that of the conditionals, and links premises with conclusions. If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily
Logical disjunction Logical disjunction In logic and mathematics, or is the truth-functional operator of (inclusive) disjunction, also known as alternation; the "or" of a set of operands is true if and only if "one or more" of its operands is true. The logical connective that represents this operator is typically written as ∨ or +. formula_1 is true if formula_2 is true, or if formula_3 is true, or if both formula_2 and formula_3 are true. In logic, "or" by itself means the "inclusive" "or", distinguished from an exclusive or, which is false when both of its arguments are true, while an "or"