State Ulpian's definition of justice.

Etymology: jus (right, law) + dicere (to speak): justice = to speak the right — the court's very name (Latin iuris-dictio → "jurisdiction") declares the ideal. The classic formulations (brief, attributed): Plato (Republic): justice is each part doing its own — harmony, "doing one's own work and not meddling." Aristotle (Nicomachean Ethics): justice as proportionate equality — treating like cases alike (and unlike cases unlike) — the deepest single sentence in the tradition; everything else is its elaboration. Ulpian (Roman law): justice is "the constant and perpetual will to render to each his due" (suum cuique tribuere) — the Digest's definition courts still quote. Justinian's Institutes: "the constant and perpetual desire to give everyone his right." John Rawls (A Theory of Justice, 1971): justice as fairness — the principles that free and equal persons would choose behind a veil of ignorance (not knowing their own caste, class, gender, luck): equal basic liberties first; then differences permitted only if they benefit the least advantaged (the difference principle) and attach to fair opportunity. Modern legal justice: process-based — the requirements of natural justice: (i) nemo judex in causa sua (no one judge of their own cause — the rule against bias); (ii) audi alteram partem (hear the other side). Procedural fairness as justice's minimum core. The dimensions to keep apart (a favourite…