Liberty is as much a matter of compulsion as duty, but where duty says to a person that he must or must not, liberty says to other persons that they … - John R. Commons

But institutional economics is the field of the public interest in private ownership, which shows itself behavioristically in buying and selling, borrowing and lending, hiring and firing, leasing and renting. The private interests become the field of intangible yet quantitative and measurable rights, duties, liberties and exposures to the liberties of others. These are various aspects of rights of ownership. What we buy and sell is not material things and services but ownership of materials and services. The correlation of engineering economics, home economics, and institutional economics makes up the whole of the science of political economics.

While mere process of thinking is the process of habits, ideals, definitions, investigations, classifications, valuations and behavior, due process of thinking, which is due process of law, is the process of correct habits, right ideals, true definitions, sincere investigation, reasonable classification, reasonable value, and justice; whereas its opposite, undue process, is perverse habit, wrong ideals, double meanings, partial investigation, class legislation, confiscation and injustice.

Legally, the term liberty means absence of duty, or rather the limit of duty.