Argumentum a fortiori (literally "argument from the stronger [reason]") (UK: /ˈɑː fɔːrtiˈoʊri/,[1] US: /ˈeɪ fɔːrʃiˈɔːraɪ/) is a form of argumentation that draws upon existing confidence in a proposition to argue in favor of a second proposition that is held to be implicit in, and even more certain than, the first.[2]