infallible logic

Translations
безошибочная логика
His argument was based on infallible logic.
Его аргумент был основан на безошибочной логике.
Definitions
Infallible logic refers to reasoning or arguments that are considered to be flawless and incapable of leading to a false conclusion. It implies a level of certainty and reliability in the logical process that guarantees the truth of the outcome based on the premises provided.