There is no reasoning of principles; no argument is required to prove fundamental rules.

Explanation

(English-origin maxim.) First principles of law — such as the right to life, liberty, and property — need no proof or demonstration; they are self-evident axioms upon which all other legal reasoning depends.

Where this applies

• A party demands that their opponent prove the self-evident truth that a person has a right to defend their own life, and the court refuses to require proof of a fundamental axiom.
• An attorney argues that the principle 'no one shall be a judge in his own cause' needs evidentiary support, and the court holds that first principles of justice are self-evident and require no demonstration.
• A government agency challenges the foundational rule that property cannot be taken without due process, demanding empirical proof, and the court holds that bedrock principles need no argument to establish.