In the sense of perfection, goodness indicates a desirable excellence; badness indicates a deficiency.
Knowledge — an excellence because it brings understanding.
Ignorance — a deficiency because knowledge is absent.
Justice — respecting rights and proper balance.
Injustice — failing to give rights their due.
Recognizing these qualities does not itself determine all associated legal rules. Appreciating justice is one matter; specifying evidentiary standards, adjudication and detailed rights in a dispute is another.