external ground; external basis
Technical term used in philosophy, law, or academic contexts to refer to a justification or foundation that lies outside the subject or system.
This claim requires an external ground.
内的根拠 refers to an internal ground or basis, while 外的根拠 refers to an external one.
Compound of 外的 (external) and 根拠 (ground, basis). The exact historical derivation is uncertain; the term is used in modern academic Japanese.