"What philosophy is, or should be, is itself a philosophical question that philosophers have understood and treated differently through the ages." (Wikipedia Philosophy p1). Philosophy can also be defined as a "doctrine: a belief (or system of beliefs) accepted as authoritative by some group or school; the rational investigation of questions about existence and knowledge and ethics; any personal belief about how to live or how to deal with a situation." (Princeton WordNet p1).
The second of the above definitions lends itself to our thesis. 'Some group or school' could be analogous to the legal profession; 'doctrine' could be analogous to the law; 'personal belief about how to live' could be analogous to an individual's virtue, morality, and ethics; and 'deal with a situation' could be analogous to entering into a negotiable instrument such as a contract. This second definition mentions most of the issues that have given rise to a wide ranging concatenation of philosophical treatise and thought concerning the philosophy behind and used in the creation of a body of laws meant to guide the individual in their dealings both in rem and in persona.
The philosophy of law could be said to trace its origins back before Plato and Aristotle established what contemporary society defines as virtue ethics (Wikipedia Philosophy of Law p1). ...
Some of these social contracts could probably even fit today's UCC definition as "negotiable instruments" (Yovel 7).
Whether these early contracts fit the Uniform Commercial Code (UCC) is not the question. The question is whether engaging in the philosophy of law is more than just a mental exercise. Hence we must first become familiar with what is currently thought of as the philosophy of law and then use some specific case examples to validate the premise that it has relevance and should not be disparaged.
Wesley Newcomb Hohfeld's analysis originally published as two articles in the Yale Law Journal in 1913 and 1917 and are "...now a standard part of legal thinking" (Walker, Oxford Companion to Law 575) is a starting point that appears to provide a reference plane from which we begin our familiarization with the philosophy of law. Hohfeld believed that philosophically, there were co-dependent and inter-related fundamental legal concepts. In his two papers he enumerated eight entities called jural correlates and jural opposites.
"Hohfeld maintains that legal analysis is frequently muddled and inconsistent because of an improper understanding of the fundamental legal conceptions. His stated goal is to catalogue and clarify these conceptions. He asserts that there are eight such entities: right (claim), privilege (liberty), power, and immunity along with their respective correlates of duty, no-right (no-claim), liability, and disability. In addition, each fundamental conception is a jural opposite to another: privilege (liberty), right (claim), power, and immunity are the respective jural opposites of duty, no-right (no-claim), liability, and disability" (O'Reilly p1).