By What Standard?

From Douglas Wilson and Randy Booth's A Justice Primer:

Autonomy seeks to replace the perfect law of God-which is perfect justice-with our own standards of justice. Justice demands an authority. By what standard will we evaluate fairness? Who will execute or enforce justice? Is this standard and authority infallible? How are the standards to be applied? Who says? These are all inescapable questions. Some standards will be used and some authority will stand behind those standards. The alternatives are limited. Essentially, we can choose between autonomy and theonomy-man's law or God's law. One of these standards will be the ultimate authority and arbiter of justice.