“In questions of law or of fact conscience is very often confounded with opinion. No man’s conscience can tell him the rights of another man; they must be known by rational investigation or historical inquiry.”

This correlates with a verse in the Holy Bible: I CORINTHIANS 10:29 KJV

Emotion also obscures facts.

Law, at de jure Constitutional jurisprudence, is limited in the scope to the law of nature and of nature’s God’s (natural law) life, liberty and property. By way of extremely brief illustration, natural law describes “That Which Is” (gravity, physics, fiscal law, etc.) The individual sovereign’s representatives are to represent the inalienable rights that are exactly the same in each and every, any and all sovereign individual(s). Those representatives are to use such tools as codes, codifications, ordinances, regulations, rules, statutes, etc. to define the order which most successfully enables and protects fulfillment of such natural law rights. Said tools are ‘NOT’ law but rather points of order. Law is to be discovered by intellect, investigation, reason, logic, observation, a non-biased historical inquiry, rationality and reasonableness.

A fact is “an action; a thing done. It is either simple or compound. A fact is simple when it expresses a purely material act unconnected with any moral qualification; for example, to say Peter went into his house, is to express a simple fact. A compound fact contains the materiality of the act, and the qualification which that act has in its connection with morals and, the law. To say, then, that Peter has stolen a horse, is to express a compound fact; for the fact of stealing, expresses at the same time, the material fact of taking the horse, and of taking him with the guilty intention of depriving the owner of his property and appropriating it to his own use; which is a violation of the law of property.” (Bouvier’s Law Dictionary) ‘Facts’, in man’s administration are to be simple facts derived from as many sources and perceptions as possible. Intent ‘MAY’ contemplate aspects of a compound fact.

An “A”theist’s conscience may differ from a “B”uddhist’s conscience, from “C”hristian’s conscience, etc. The ABCs of conscience, are most often expressed by opinion. And, even though an opinion (conscience) is a belief or conclusion held with confidence, it is not substantiated by positive knowledge, proof, fact or law. The de jure American jurisprudence is to be administered at fact and law (not morality, ethics, religion, etc.)

Joe and Mike are right on.

Why is my liberty judged of another man's conscience ?

Well said, Mike. Although I am confused as to what Johnson means ... how about the responsibilities of a jury? In the end, it is a man's conscience that weighs the decision of guilt. We vote with our consciences, we judge 'right and wrong' with our consciences, all matter of choices are matters of conscience. In a free republic, conscience is the guide and final check upon the actions of ourselves and each other. Even after "rational investigation or historical inquiry" our decisions/choices/actions are matters of conscience -- otherwise we are not really free, nor could we accept responsibility for the consequences of our actions.

Confounded or confused with private opinion . Spiritual law, by way of conscience, The law written in fleshly tables of the heart, can be manipulated, by reason of private opinion.
That is why nether God or our Constitution is a respecter of persons. No private opinion needed. We are set at Liberty and freedom.

a quick note* the phrase: "The simple fact of the matter is" derives from the common law definition and application of "fact".