In my previous article, I covered the history and development of legal philosophy from Ancient Greece to the Early-Modern period. This article explores more recent developments from the 19th century until the present. It also serves as an introduction to contemporary issues with jurisprudence. These developments are ubiquitous with debate, particularly between the theories of Legal Realism and Legal Positivism. Both theories have widespread discussion by various philosophers, all with interesting and unique ideas.
Legal philosophy in the 19th century was expounded upon greatly by two philosophers in particular - Jeremy Bentham (1748–1832) and John Austin (1790–1859). The mind behind Utilitarianism, Bentham was rigorous in his work on jurisprudence, he was analytical and intuitive, however, most of his work was unpublished before his death, and therefore was not read nor engaged with by intellectual thought until the 20th century. However, the work of John Austin presented Bentham’s legal philosophy to a 19th century audience. The works of Bentham, through Austin’s research and discussions, started significant developments in legal positivism dominating 20th century thinking.
Bentham’s legal philosophy tends to be divided into two distinct themes. His earlier works focused on critiquing common law theory and anatomizing its elements, attacking the very idea of common law meticulously. His later works involved developing Hobbes’ ideas on sovereignty, and command-law theory.
To start with his first theme, Bentham believed that common law was far from what law ought to be. In both theory and practice, he believed it was unfit to be the basis of the English legal system. He attacked Blackstone’s Commentaries on the Laws of England (1765–69), in which he attempted to collate the history of the common law system in England into a collection of guiding principles. Blackstone promulgated the idea that due to its long history and reputation, common law had a certain “wisdom” that “the declaratory part of the municipal law…depends not so much upon the law of revelation or of nature, as upon the wisdom and will of the legislator”.  This gave it a legitimacy that caused the English people to accept its authority. In A Fragment of Government (1776), Bentham heavily criticised Blackstone and other legal minds in their fallacy of describing law as what it is rather than how it should be. This mistake would halt the progress of legal reform, and make the law stagnate, rather than something to be improved upon. So much so, it could not handle the socio-economic revolution and change towards the end of the 18th century.
Bentham also took issue with the complex, almost labyrinthine, language used in law, stating “the technical arrangement of English Law…was ‘confused’ and ‘unsatisfactory”. He held this opinion so strongly that he maintained that it was “a sink that with equal facility swallow any garbage that is thrown into it.”  Bentham believed that this was to preclude ordinary citizens from understanding the law and to sustain the myth that legal professionals are experts of “artificial reason”, suggested by Coke.  Echoing Hobbes’ view, Bentham believed that the instructive quality of the law would not be viable, if the language used was not readily accessible to the majority of the people, to which it was to serve as a guide. He maintained that:
“such a veil of darkness, such a cobweb work of sophistry, has been thrown over the face of penal jurisprudence, that its lineaments can scarcely be laid open to public view but with great difficulty”. 
Bentham’s attack on common law also extended to the function of judges. He believed that law, on a case-by-case basis, could not serve to instruct or prohibit actions, nor guide those to whom it applied, and could not be viable as law. Bentham referred to the common law as “dog-law”. He provides an analogy, stating that a dog’s behaviour is observed then instructed as to why it is bad, and then punished - he relates this idea to common law;
“They won't tell a man beforehand what it is he should not do - they won't so much as allow of his being told: they lie by till he has done something which they say he should not have done, and then they hang him for it. What way, then, has any man of coming at this dog-law?”. 
This essentially made future compliance unfeasible, as the law was applied retrospectively. Just as a dog is given no rational means by which to prevent its misbehaviour, so too does this apply to judge-made law. A judge will imply liability but provide no precaution on how to avoid said liability in the future.
Finally, Bentham advanced the Hobbesian discussion over law and sovereignty, and the relationship between both subjects. Bentham’s definition of law is “an assemblage of signs declarative of a volition conceived or adopted by the sovereign of a state”.  This follows the command-law model, illustrating his rejection of common law further. Bentham also discussed sovereignty to explain the unified nature of the legal system, as well as what makes laws valid within that system. He suggested that a law is only a law if it has the correct relationship with a legitimate sovereign legislator. He also discussed the relationship of people, or communities of people with the law, and in-turn the sovereign. He explained that the power of the sovereign comes from the people themselves; their obedience and recognition of laws issued by the sovereign. The sovereign and their people have a dynamic synergistic relationship. He maintained that it was subject to change, but this would rarely happen - as citizens were prone to conformity, and there was a social expectation from their peers to be obedient. Bentham’s work was the antecedent for an idea in the 20th century that the authority and power of the law relied on intricate social expectations, interactions, and beliefs within a community.
John Austin was professor of jurisprudence at University College London from 1826-32, but was relatively unheard of during his tenure. The work of Austin was significant in the development of legal positivism in the 20th century. He was significantly influenced by Bentham's large body of work. However, Austin had access to a small portion of this work, and so could not fully appreciate the novel, complex ideas Bentham had. As a result, Austin’s work is seen as a more accessible version of Bentham’s legal positivism. Austin is credited with being the originator of the maxim “the existence of law is one thing; its merit or demerit is another”.
Where Austin differs from Bentham is in his discussion on command law theory. He suggested his own idea; the Imperative Theory of Law. This idea can be seen through Austin’s Lectures in which he states “Every legal duty is the duty to do (or forbear from) an outward act or acts, and flows from the command of the sovereign” and “the party upon whom it is imposed is said to be legally obliged, because he is liable to the means of compulsion wielded by that superior”.  Austin stipulates that commands are necessary instructions that prescribe the desires of a sovereign. Austin described the sovereign as an entity which commands obedience from the majority of its citizens, but who is not subject to any authority itself. This obedience is more simple than that described by Bentham’s works, it requires only a correlation between the desire of the sovereign and what the majority of the community actually does. For Austin, law is not a distinct catalyst, and therefore why it causes obedience is not important. Consequently, the threat of a punishment or sanction is a necessary motivator for obedience. Beginning in the late 19th century, many philosophers began to refute this form of positivism. However, a more holistic and authoritative refutation emerged in the 20th century.
Legal positivism dominated the 20th century. The most prominent positivist theories were developed by H.L.A Hart (1907–92), and Hans Kelser (1881–1973). Anti-positivists such as Ronald Dworkin (1931-2013) and Thomist John Finnis, developed critical responses to positivism. A student of Hart’s - Joseph Raz began working on his own legal philosophy within the framework of positivism, developing important distinctions between both Hart and Kelsen’s stances. Realism found its roots in the 20th century with two schools emerging: one in Scandinavia - which was concerned with the philosophical ramifications of positivism - and an American school, concerned with the more practical aspects of legal philosophy.
Hans Kelsen was radically against command law theories. For Kelsen, the most significant issue in legal philosophy was communicating the law’s claim to authority. Kelsen believed the law to be an instrument that is directed at legal officials, who then instruct the wider community of citizens on what sanctions or regulations apply to them. He rejected the idea that the force of the law could be derived from morality. Like most positivists, he noted that laws could fail to be moral. He questioned this view by questioning how one can explain the differences between threats of brute force and legal demands. For example, when a judge decides a case their authority descends from the legal system that allows the judge to make such decisions, whilst simultaneously being subject to procedural constraints by the legislature. Kelsen questioned what gives those rules authority over others. He posited it may be a constitutional power, entitling the legislature to enact substantive rules overseeing the decisions of the court. This entails a specification of who can and under what circumstances the power of a judge may be exercised. This leads to the question of what gives the constitution its rights. Kelsen maintained that this leads to the fallacy of infinite regression, a logical circle or “unquestioning obedience to certain truths”, as one posited source of authority is granted authority by another.
Kelsen was greatly influenced by Kant. He followed the transcendental strategy of argument that Immanuel Kant (1724-1804) popularised. That is, a certain phenomenon must necessarily infer the existence of whatever grants it an explanation. Given that law claiming authority is undisputed, the only way to avoid this logical circle is to make an assumption that the fundamental source of legal authority is derived from a grundnorm, or a “basic norm”, substantively meaning “we must obey a constitution”. Kelsen purported the pure theory of law as a science, its name finding foundation in its function; seeking “to preclude from the cognition of positive law all elements foreign thereto”. However, the issue with the isolation of a concept in a transcendental argument is a vulnerability to existential objections denying the reality of what a theory explains. The law claims authority, but this could only be apparent, not real. Hart’s legal positivism abstained from transcendental arguments, but still focused on the same problem of legal authority as Kelsen.
Hart spent his career in academia at Oxford, influenced by analytical philosophers such as Ludwig Wittgenstein (1889-1951) and jurists like J.L Austin (1911-60). Hart utilised linguistic philosophy to investigate central problems of jurisprudence. Hart was critical of command law theories, especially those of Bentham and Austin. He criticised Austin’s “apparently simple elements of commands and habits" specifically as they only focused on sanctions, rather than the instances in which the law grants legal powers to individuals - such as the execution of a will. These instances are tenets of legal systems, and Hart posited that command theories do not grant sufficient explanations for them. Hart further discussed this problem, maintaining that the idea that all law necessitates sanctions is an error. He deemed Austin’s theory inadequate as it does not entertain “the idea of a command”. Hart utilises an analogy of a robber, stating that if the law is just threats, then a discussion of obligations makes no sense, as no one believes they are obliged to consent to a robbery, forfeiting their property due to an obligation. Hart agreed with Kelsen that the law claims authority in its right to tell people what they ought to do, rather than what they must not.
Hart posited that upon the existence of a legal system so too is there also a “rule of recognition”. This rule sets out the elements of legal validity that a rule must fulfil in order for it to qualify as a legal rule. This is not the same as a grundnorm. It is a psychosocial phenomenon that finds its foundation in sociology and psychology - the criteria by which legal officials determine legal validity, and the fact that those officials view the criteria as mandatory. For example, the Bill of Rights 1689 is a source of legal authority as almost every justice of the UK courts treats constitutionality as an element that necessitates legal validity.
Contrary to the work of Kelsen, Hart’s positivism is not a “pure” theory of law. Hart claimed that the law can be explained behaviorally, in regard to judges. Hart was of the same opinion of Kelsen that laws can be unjustified morally. He disagreed that the law’s existence is dependent on the practice of judges. If the UK justices deemed the Bill of Rights unconstitutional then its legal validity would cease to exist.
Joseph Raz explored the idea of law’s claim to authority, in greater detail than Hart and Kelsen. Raz expounded upon what authority truly means, defending the “service conception of authority”. This suggests that the law is a guiding force that advises while instructing, doing so better than the subjects of the law would do without this instruction - “to help them act on reasons which bind them”. Raz maintained that some laws fail to satisfy this criterion, but laws that only a rule of recognition could possess genuine authority if it was derived from a source, such as “enacted by the Assembly” or “proclaimed by the Queen”. The reason for this is that if the law is not comprehensible, and autonomous of the moral reasoning on which it is based, then the law cannot provide the service this conception is based upon. This legal positivism determined that the aforementioned norms must be part of the law, but only due to their social sources. Raz formulated a semi-cohesion of both positivist and command law theories, particularly that the law is a system or social norms, performing a certain service to the reasoning of the citizens that are commanded by it.
Ronald Dworkin was a critic of legal positivism. He argued that ethical reasoning serves as the foundation for answering constitutional questions. The summary of his views can be found in Hart’s The Concept of Law - “Dworkin argues that our law includes not only norms [...] but also moral principles that provide the best justification for the norms found there”. He was a staunch critic of Hart’s work, specifically as he had denied that ethical considerations were necessary for law, unless they constituted a part of the societal rule of recognition. Dworkin critically argued that Hart’s discussion on the rule of recognition in which all legal officials reflected critically left little explanation as to why these officials had an obligation to follow these conceived rules. However, it was not Hart’s intention to demonstrate the rule of recognition in detail, but rather to explain the necessary elements for a legal system to exist. Hart understood that legal officials may find the rule of recognition obligatory for a myriad of reasons, but that this might be an error too.
Dworkin in his later works expanded on how ethical considerations determine what the law is. He argued that a “constructive interpretation” of norms constitutes the law of a particular legal system. This interpretation is one that explains the source-based norms in regard to moral principles like justice and accountability, whilst relying on explanatory ethical principles to provide justifications for the legal system in which it exists. It is a “process of imposing purpose on an object or practice in order to make it the best possible example of the form or genre to which it is taken to belong”. This rather complicated view did not have many supporters; it resulted in an unusual consequence - that no one may truly know the laws of legal systems, as the greatest constructive interpretation may have not been discussed. Hart interpreted Dworkin’s discussion on the rule of recognition of anglophone common law systems, in which legal officials produce coherence between decisions in current cases and previous decisions.
John Finnis had a more determined philosophical criticism against legal positivism than Dworkin. He believed that any sociological theory must identify its central ideas to become fully developed. Finnis determined this to be the “central case method” - in which “there is a central case of law - a good, stable form of social ordering with reference to which all other cases [...] ought to be understood.” These cases are deemed central as they have a legitimate ethical obligation to follow the law. Finnis determined that this was the purpose of legal theory - to identify the characteristics that morally justify obligation and obedience. Hart acknowledged that whilst this was the case, cases can be found without regard to their ethical qualities.
Finnis’ natural law approach highlighted a difficulty regarding legal philosophy in the late 20th century - the problem of the Nazis. The Nazis had a legal system - one that was intrinsically immoral - sanctioning based on race, ethnicity, religion and disability. At the Nuremberg trials, officials of the Nazi party were tried and convicted for actions they believed were “lawful” - even resulting in executions. Finnis and other jurists believed Nazi law not to be a “central case”, but a defective version. This meant that it was just to prosecute members of the Nazi party for their gross immorality. Contrastingly, Hart and other legal positivists separated the issue of whether the laws in Germany were unjust to whether the immoral character of the Nazis warranted prosecution, even though their actions were lawful. Despite their actions before and during WW2 being most certainly immoral. Hart believed that some good arises from differentiating between what the law is, and what is morally right, believing that it reminded people that some laws are morally unjust, and in instances where this occurs, accountability of those who believe themselves to be lawful but are morally corrupt is paramount.
Whilst legal positivism dominated the 20th century, a very different influential approach developed apace with it. This approach is known as legal realism. This conception was divided into the aforementioned American and Scandinavian schools of thought. The two figures who spearheaded this were Karl Llewellyn (1893-1962) and Alf Ross (1899-1979). Ross was a jurist and a legal philosopher. Llewellyn was an influential lawyer and an accomplished professor. The main force behind these two different thinkers and their respective schools was a scepticism of the concept that laws themselves can elucidate the behaviour of legal officials. Realism relies on a worldview in which reality is described by natural science.
Ross believed this worldview to be obvious. He was heavily influenced by the logical-positivism theories of the Vienna Circle. He had an empirical view, in which only those things that can be described by science truly exist. As a result of this, Ross averred that the sociological norms of obligation, rights, or justice - don’t really exist. He “changes the fundamental perspective from being justificatory and normative to being empirical and descriptive”. However, Ross did not extend this to laws and legal systems. He maintained that legal judgments such as “the acceptor is obligated to pay the bill of exchange on the due day for payment” could be interpreted as the judge strongly advising the acceptor to pay the bill on time, otherwise he shall face sanctions. Hart criticised this approach, believing this theory unsatisfactory in regard to normative law. However, Ross was uninterested in the normative concept of law. His aim was to interpret legal terms, in a way that demonstrated compatibility with his empirical view. Through this, Ross attempted to explain sociological phenomena in law, through a scientific lens.
Whilst Karl Llewellyn is seen as the most prolific American realist, the founding father of this idea was Oliver Wendell Holmes Jr. (1841-1935). In 1897, his lecture “The Path of Law” began a discussion on the relationship between law and morality. It also brought discussion on the indeterminate nature of the law - in which judges are influenced by considerations outside the legal sphere, for example, their own views on economic issues. These ideas were developed further in the work of Llewellyn, who had been influenced by the proto-realist free-law movement of the early 20th century. To Llewellyn, in most appellate cases the law is indeterminate - statutes, precedents and other items of authority are left unused to justify unique decisions. This indeterminacy primarily stems due to the existence of contradictory but similarly legitimate rules of interpretation - resulting in instances where individual legal sources can be read in several different ways. Llewellyn evidenced this claim through the US courts, which supported two contradictory elements of statutory interpretation. The first being “a statute cannot go beyond its text” with the other being “to effect its purpose a statute may be implemented beyond its text”. For realists like Lleweylln, developing an answer to why a legal official would reach such a conclusion, despite the law and legal reasoning not requiring it. Llewellyn formulated a two-prong “construction” to precedential interpretation - strict and loose. For Llewellyn, legal officials will always utilise precedent in highly specific ways, distinguishing it from current cases, or utilise it abstractly making it binding to current cases. This led Llewellyn to believe that judges are not truly bound by precedent.
Llewellyn believed that judicial decisions involve predictable and repeated patterns. He focused on commercial law, arguing that the judiciary enforces the sociological norms found in business culture. Famously, he recalled a series of cases from New York. In which courts had been applying rules involving buyer-seller rejection of goods by formal statement. Consequently, the stating of these objections yields the ability to object in other ways. Llewellyn found that these rules were applied harshly. By studying the facts of the case it illuminated that the market prices had been falling, and the buyer wished to void the contract. The court was “sensitive to commerce or to decency” and thus utilised this rule to stop the contract from becoming void. This upheld the commercial notion that buyers must honour their contracts, even when market conditions change. To Llewellyn, the “background facts, those of mercantile practice, those of the situation-type” determine how decisions are made in cases.
Llewellyn and other realists highlighted the importance of nonlegal variables in judicial decisions. Through this, they emphasised the importance of social science research to better understand the evolution of the law. This interdisciplinary thinking caused a change to how the law is taught, instead of decisions being explained by reference to legal reasoning only - sociopolitical influences and the ideology of the judiciary were taken into account.
Law has developed exponentially from Ancient Greece to Present Day. As societies have developed, the law has always been a central feature in philosophical thinking. This fact remains true to this day. Jurisprudence often builds upon older ideas, changing them into something new entirely. From Kelsen's legal positivism stemmed Ross’ realism and so on. It is without question that within the next century there will be new developments in legal theory. As future jurists and their discourses evolve and develop, so too will breakthroughs in legal philosophy.
Bibliography / Works Cited
 Bl Comm vol 1 s2 54.
 Phillip Schofield, Jeremy Bentham and H.L.A. Hart’s ‘Utilitarian Tradition in Jurisprudence, Jurisprudence (2010).
 Jeremy Bentham, A Comment on the Commentaries and A Fragment on Government (1776)
 Co, Inst (1628) bk 2 ch 6 s138.
 Jeremy Bentham, The Works of Jeremy Bentham (John Bowring, 1843)
 Ibid vol 5 231-237.
 Jeremy Bentham, Bhikhu Parekh (ed) Critical Assessments Volume 3 (Routledge 1993)
 John Austin, Wilfred Rumble (ed) The Province of Jurisprudence Determined, (Cambridge University Press, 1995) 157.
 John Austin, Lectures on Jurisprudence, (Henry Holt and Company, 1875) 198, 194.
 Hans Albert, Traktat über kritische Vernunft (Tübingen: J.C.B. Mohr, 1991), 15.
 Hans Kelsen, Pure Theory of Law and Analytical Jurisprudence (Harvard Law Review, 1941) 63.
 ibid 44.
 H.L.A Hart, The Concept of Law (Oxford University Press, 1961) 18.
 ibid 20.
 ibid 103.
 Joseph Raz, The Morality of Freedom (Oxford University Press, 1988) 56.
 Hart (n 13) 18.
 Francisca de Graaf, Dworkin’s Constructive Interpretation as a Method of Legal Research (LaM, 2015) 1.
 Matthew Hill, Methodology in Legal Theory: Finnis and His Critics (NZLII, 2015), 167.
 Jakob Holtermann, Alf Ross: On Law and Justice; Editor’s Introduction (Oxford University Press, 2018) 32.
 ibid 13.
 Karl Lleweylln, Remarks on the Theory of Appellate Decision and the Rules or Canons about How Statutes Are to Be Construed, Vanderbilt Law Review, 1950) 401.
 Michael Sinclair “Only a Sith thinks like that”: Lleweylln’s “Dueling Canons,” One to Seven (N. Y. L. Sch. L. Rev, 2005) 960.
 Karl Llewellyn, The Common Law Tradition: Deciding Appeals (Columbia Law Review, 1961) 126.