More on Stand to Reason from Infoplease:

• Stand to Reason - Stand to Reason (To), or It stands to reason, is the Latin constare, constat. Source: Dictionary of ...
• reason: meaning and definitions - reason: Definition and Pronunciation
• stand: meaning and definitions - stand: Definition and Pronunciation
• Dictionary of Phrase and Fable: S - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "S"