To begin with, we need to clarify that Tamanahas article is not without value, as Tamanaha has made some valid arguments, which cannot be disputed. Throughout his article, Tamanaha gives us a good account of what traditional legal positivism stood for and how contemporary legal theorists have transformed this important legal theory. As a result, it is only necessary to give a brief account of the historical background of legal positivism at a later stage in the dissertation.
For now, we will turn our attention to the issues within the article, the most problematic claim in the Tamanaha article is one where he states that legal positivists have divided into two different groups whereby both argue about legal theories and “turn their backs on real world matters”.  This is something that I strongly disagree with and will be spending a large section of the dissertation arguing against this point. Apologies are made in advance, as it may seem to the reader that we are going off context but it will become clear at the end of this section that Tamanaha has made a critical mistake in making this claim. My line of argument will be to look at Brian Lieter’s writings in “Legal Realism and Legal Positivism Reconsidered” and dispute Tamanaha’s statement through the link between American Legal Realism and Legal Positivism. Leiter argues at the outset the there are two common misconceptions within jurisprudence that he wants to rebuff. Firstly, that Legal Positivism and Legal Realism are not incompatible from a conceptual level. Secondly, that Legal Realism has been gravely misunderstood even by the central character of modern legal positivism, Hart. 
It seems in Leiter’s view that only by comparing Legal Realism to Legal Positivism on a conceptual level can Hart argue that they are opposed to one another. He adds on that “Positivism is essentially a theory of law-a theory, in part, about what is distinctive of any society’s legal norms–Realism is essentially a descriptive theory of adjudication, a theory about what it is judges really do when they decide cases.”  In order for Legal Realism to work it must presuppose a theory of law and this is where according to Leiter Legal Positivism comes in.  Leiter admits that Legal Realism cannot ascertain to be a theory of law on a conceptual level because quite frankly is it a “philosophical mess” but he suggests that there are links between Legal Positivism and Legal Realism on an Empirical level. The empirical level will consider “whether or not legal rules causally determine judicial decisions.” Leiter goes on to add that even though Hart was aware of this possibility he has not given a convincing argument to dispute the link at the empirical level.  One has to wonder why Hart stayed clear of such debates, was there something he was afraid of discovering.
Leiter is insistent that anyone writing on Legal Realism should fully understand what it stood for before attempting to define what it is or what it does. He adds on that many of the main characters within Legal Realism like Llewellyn, Frank, Radin, Moore, Yntema, Cohen, Oliphant, Green, and Hutcheson wanted to achieve the goal of “understanding judicial decision-making and, in particular, shared certain substantive views about how adjudication really works.”  Leiter presses the argument that Legal Realism is a descriptive theory about how judges actually decide cases based on the facts of the cases instead of looking at legal rules. Although, it does seem clear that judges can predict cases if they fall within distinct patterns. This process allows judges and lawyers to predict the outcome of a case where the facts fall within a “situation type” which the outcome of that type has already been determined.  Oliphant clarifies this point when referring to commercial law and dealings between parties and the fact that judges may rely on “commercial norms”  (i.e. what would reasonably be expected of both parties in this situation) in order to decide a case.
Therefore, it seems that Realists wanted to identify and describe the way in which decisions are made by judges.  This is very similar to the way in which conceptual analysis works, which demonstrates that there is some sort of link between Legal Realism and Legal Positivism. Legal Realists wanted to push forward the idea of an “empirical theory of adjudication” as it gave us the best opportunity to fully understand judicial decisions.  Of course, such a theory would only work if Realists were able to ‘presuppose’ an existing theory of the concept of law. 
Leiter, like many others before him makes it clear that Legal Positivism is a “theory of law or about the nature of law”.  What this tells us is that we must use this theory as a way of understanding and analysing our “concept” of law. This is a task which involves establishing the “criteria of legality”  and determining whether a certain norm is a legal norm. Leiter then covers the two most important theses of the Positivists’ theory. The social thesis (which concludes it is society which decides what will count as law, “social fact”) and the separation thesis (which states that what the “law is and what it ought to be are separate questions”).  If Leiter’s work is read carefully, it will become clear where Hart went wrong in his analysis and the fact that Hart offers no conclusive arguments to rebut the connections between Legal Positivism and Legal Realism. So if Hart misunderstood Legal Realism himself it is inevitable that those who read Hart and interpret his work will be making the same mistakes.
There are two clear arguments as to why Legal Realism and Legal Positivism are connected. Firstly, both Legal Realists and Legal Positivists accept that law is indeterminate. According to Leiter, Realists argue that trying to determine if a law is justified, based on “legal rules” has not worked in the past and that is not something that Realists want to do.  Therefore, Realists only wanted to find out what it is that makes judges decide cases in this way. Similarly, Hart accepted that legal rules are indeterminate because “there is a limit, inherent in the nature of language, to the guidance which general language can provide”.  This was because language is, in Hart’s opinion, “open-textured”:
“There will indeed be plain cases constantly recurring in similar contexts to which general expressions are clearly applicable (“If anything is a vehicle a motor-car is one”) but there will also be cases where it is not clear whether they apply or not. (“Does ‘vehicle’ used here include bicycles, airplanes, roller skates?”). The latter are fact-situations, continually thrown up by nature or human invention, which possess only some of the features of the plain cases but others which they lack.” 
This then makes it clear that even the most celebrated 21st century legal positivist is aware that there are similar features between Legal Positivism and Legal Realism. The second argument is that both Positivists and Realist agree that legal rules do not determine decisions in some cases.  Realists for example argue that it will be up to judges to decide how the use a range of tools available to them when interpreting previous decisions. As Llewellyn puts it judges have the discretion to interpret a case “strictly” or “loosely” and that in most cases their interpretation will be “recognised, legitimate, honorable”.  It is through adjudication that private parties, such as individuals or corporations are able to sort out legal disputes. In addition, adjudication is there to review any disagreements between private parties and public officials. If then judges are involved in the legal process whereby they have to assess evidence and arguments presented to them about legal issues surely this is something which can be considered ‘a real world matter’. Tamanaha has failed to consider these sorts of arguments in his article and as a result has opened himself up to criticism.
Contrary to Tamanaha’s argument, Legal Positivism does deal with real world matters, as adjudication is a real world matter. Legal Realism is about highlighting how law operates in practice, and Realists wanted to locate law in its broader context (not separate). Leiter also points out that Realists challenged the ‘myth of legal certainty’- by highlighting indeterminacy of law. More importantly to our task here, it is clear that Legal Realism concerns law and study of law as an inherently practical activity associated with the “real world”.  As a result, these findings suggest that Tamanaha was wrong to make such an erroneous claim without looking at the evidence to back up his premise. There are also a number of other faults with Tamanaha’s article. In an attempt to convince the reader, Tamanaha has selected specific writings about legal positivism, which heavily criticise it in order to suit his side of argument, whilst ignoring arguments that are made in favour of legal positivism. He quotes Waldron who said that ‘these analytical discussions tend to be flat and repetitive in consequence, revolving in smaller and smaller circles among a diminishing band of acolytes’  . What Waldron believes is that we should go back to traditional legal philosophy in order to improve our understanding of the concept of law. He states that in legal philosophy:
“there is less of a sense of a canon of great books stretching back to the dawn of time. If there is canonical work it is H.L.A Hart’s book, The Concept of Law, which analytical jurists read over and over (and the squabble amongst themselves as to what it means and whose position is now closest to what Hart’s is taken to be). Since Hart Developed his theory by criticizing the nineteenth-century jurisprudence of John Austin, there is also some half-hearted discussion on Austin’s work. Beyond that however, the canon of legal philosophy is attenuated and non-existent.” 
Of course, it is true that there hasn’t been any standout publication on legal philosophy after Hart published The Concept of Law, but that does not mean that we should go back to the traditional ideologies on legal philosophy. Hart proved that some of the original ideas behind legal philosophy are unpractical in a modern society thus is it unproductive to keep applying them when trying to ascertain our concept of law. So common sense and reality would make us reject what Waldron suggests. Tamanaha then considers Twining, who has asserted that positivist debates are now ‘repetitious, trivial, and almost entirely pointless’.  Twining comes across as a great admirer of Bentham whose work is highly valued, however, Twining believes that Bentham should not remain as a historical figure in legal philosophy. For Twining Bentham’s “aˆ¦version of legal positivism; a more flexible and subtle conception of sovereignty than Austin’s; his penetrating attack on natural right; his progressive ideas on punishment; and his theory or adjudication” remain important topics.  In fact, Twining goes one step further to suggest that we should go beyond Bentham’s work and look at the work of Augustine and Plato to help us understand issues we deal with today.  Whilst Bentham’s work was crucial, it is important to remind ourselves that what he produced was suited for the 19th century, thus it seems unlikely that it will be beneficial in dealing with issues in a contemporary society. With regards to going beyond Bentham, it is impossible to conceive how ancient ideologies would help us deal with modern issue and therefore Twining’s suggestion is on the verge of being absurd.
Tamanaha also refers to Schauer’s work to argue that ‘large numbers’ of American law professors believe that ‘analytical jurisprudence in general, and the debates about legal positivism in particular, are the largely irrelevant preoccupation of a small group of socially unaware but philosophical obsessed pedants’.  The simple explanation to this is that almost everyone involved in legal philosophy is a positivist.  Even Tamanaha accepts that legal positivism is the dominant legal theory of law, as the first paragraph of his article states that: “Most legal philosophers agree that legal positivism is the dominant theory of law today.”  As a result, it is extremely difficult to argue on anything more than marginal issues as the main issues have already been agreed upon.
Therefore, until we have another legal theorist like Dworkin or Hart who is able to come up with new and radical ideas, unfortunately, marginal arguments is all that is left for contemporary legal positivists to debate. Tamanaha has presented some inconsistent arguments in support of his position. Right at the outset, he admits that legal positivism is “by far the biggest camp within legal theory”  but at the same time attempts to argue that it is no longer relevant. It is simply irrational to describe a theory as being both dominant and irrelevant at the same time, Tamanaha has either set out his article to be extremely provocative, or he has not really planned his arguments.
Nonetheless, Tamanaha then moves on to explaining why legal positivism has reached this point of being irrelevant. One of his arguments is that “for much of its existence, the primary foil for legal positivism has been natural law theory. But natural law theory no longer has the primacy it once did.”  Yet, Tamanaha then says that due to an agreement reached by natural law theorists and legal positivists on certain issues legal positivism has ‘lost and important reason for being’.  Here I find either muddled logic or else an outrageous sleight of hand in Tamanaha’s argument. It is astonishing how a professor who, according to Washington University in St Louis, is a “renowned jurisprudence scholar and author”  would make this sort of argument. Natural law theory might have hampered the complete domination of legal positivism but Tamanaha himself admits that natural law theory ‘no longer has the primacy it once did’. How can a legal theory lose a reason for being if it is still the dominant theory after all this this time? In fact, Tamanaha is completely wrong as legal positivism is easily the best theory of law and there does not seem to be a theory out there that can match it.  Tamanaha seems to be confused as to what legal positivism stands for, namely that it seeks to provide a better understanding of the ‘nature of law’  and if a new idea comes along positivists are willing to adopt it. Positivists believe that law is manufactured by humans and thus when we establish a law we have to critique it in order to establish whether it works, this was a fundamental idea in Bentham’s principle of utility.  Churchill once said, “I am an optimist- it does not seem to be much use being anything else.”  It has become clear that Tamanaha’s reasoning as to why legal positivism is in a problematic state is completely flawed as natural law only had a marginal effect on the dominance of legal positivism.
The most surprising error in Tamanaha’s article is his attribution to Hart’s success in the Concept of Law as on one of the reasons legal positivism has reached this point. Tamanaha writes that Hart “established the parameters of the current understanding of legal positivism”. Tamanaha goes on to add that “legal positivism today remains trapped within Hart’s paradigm.”  Either Tamanaha has misunderstood Hart’s writing or he has completely failed to grasp it. Hart made it clear in The Concept of Law that his interpretation of the concept of law is “quite ‘open’ in that it does not forbid the extension of the term.”  Therefore, how can legal positivism be ‘trapped in Hart’s paradigm’ if Hart himself has admitted that this is not a conclusive answer of what the concept of law is and that from time to time this term will need to be expanded in order to be applicable in a modern society. Tamanaha could at least afford Hart the courtesy of fully reading and understanding his work before making such erroneous presumptions, which do not portray Hart’s objectives.
Yet, Tamanaha’s misinterpretation of Hart’s work does not stop there. One of his other arguments is that legal positivism through the separation thesis allows us to be in a better position to challenge evil law. Tamanaha relies on a quote from Hart who said that:
“So long as human beings can gain sufficient cooperation from some to enable them to dominate others, they will use the forms of law as one of their instruments. Wicked men will enact wicked rules which others will enforce. What surely is most needed in order to make men clear sighted in confronting the official abuse of power, is that they should preserve the sense that the certification of something as legally valid is not conclusive of the question of obedience, and that, however great the aura of majesty or authority which the official system may have, its demands must in the end be submitted to a moral scrutiny.” 
According to Tamanaha, only if we separate the question of law and morality we can be in a position to judge whether a law is moral or not, Tamanaha writes that Hart is “Reminding everyone of the separation between law and morality, according to this view, should enable citizens and legal officials to recognize, resist, and disavow evil law.”  To drive this point home Tamanaha also relies on Schauer’s work,  but in a few pages within the same work Schauer concludes that the separation of law and morality does not necessary allow people to resist bad law.  To add further misery to Tamanaha’s argument, Bix writes that there are no conclusive arguments “either logical or psychological, for favouring legal positivism or natural law theory (or any other alternative) for the resistance to evil law.”  Again, Bix is another source Tamanaha has quoted in his article but somehow he has either misread his own sources or has chosen to simply construct them in a way which would better suit his argument. In summary, it has become clear that Tamanaha has presented a number of unfounded arguments, which can easily be rebutted. In fact, some of his arguments come across as unprofessional and it is surprising that that someone who is highly regarded in legal philosophy would see any value in presenting such arguments to the reader. Having discovered that Tamanaha’s claim that legal positivism does not connect with real world matters is misguided, we will now move on to the second part of the dissertation, which will argue that contrary to Tamanaha’s belief the separation thesis is in fact false.
Separation Thesis is False
One of the key arguments Tamanaha makes in the article is that the shift away from traditional legal positivism has had a wider affect to the point that one of the fundamental ideas behind it namely, the separation thesis, has been dramatically transformed to a point where it no longer resembles the original ideas.  Looking at legal philosophy from a historical context, it is clear that Bentham’s contribution helped shape the way in which law is perceived today. As a result, it would be almost impossible to talk about legal positivism without mention his work. Classical legal positivism as portrayed by Bentham and Austin suggests that the notion of law is simply a command of the sovereign, which obliges subjects to obey the law and gives official authority to carry out punishment. Modern legal positivists adopt a considerably more sophisticated approach to the concept of law, but, like their distinguished predecessors,  they deny the relationship between law and morals. 
Bentham single-handedly sought to transform English common law in order to achieve a greater good in society.  Through his critical analysis of the common law Bentham made it possible to construct a comprehensive theory of law. Bentham wanted to unmask the true meaning of the common law and make all of the common law’s misconceptions clearer.  In his opinion, the common law was so indeterminate, and in such chaos that it was close to being pervasive. His main argument was that in order to achieve clarity and certainty common law had to be written and recorded in a manner, which could be traced when a similar legal issue arises, thus allowing for them to be deal with in the same manner throughout England.  Bentham wanted to organise the common law in a way that it could control the behaviour of society as citizens would have a clearer idea of how they would be punished if they disobeyed the law.  In addition, by systematically setting these rules it meant judges had less power in making the law and it made it easier to understand your legal rights and obligations.
John Austin followed in the work of his predecessor as he advocated the idea of commands as notions of law. Austin was concerned about state power and which laws subjects had to obey. It can be argued that both Bentham and Austin wanted to achieve a greater understanding of the principal features of the law. However, it has been suggested that Austin’s definition of law as commands is limited in its application only to criminal law.  In addition, other writers have observed that whilst Bentham was concerned about a single ‘complete law’ Austin wanted to create a science of law.  Austin also made it clear that what the law is and what it should be are two separate questions and they should always stay separate.  It is in no doubt that Bentham and Austin laid the foundations for modern legal positivism. However, their ideas have been considerably refined, developed, and even rejected, by contemporary legal positivists.
H.L.A. Hart is often credited with providing a more sophisticated account of legal positivism than provided in Bentham and Austin’s writings. In doing so, Hart advises us that we must apply analytical, linguistic and philosophical techniques to the study of law in order to achieve a greater understand of the concept of law.  In The Concept of Law, Hart made this point clear from the outset in the preface that his task is about achieving a “descriptive sociology” [or in other words, hermeneutic description] thus a deeper meaning in the nature of words and law.  Hart considers legal concepts and the ideals we may have about the law and legal systems in a different point of view. He asks questions which had not been asked before, focusing specifically on the conceptual context of law. Whilst advocating some of the previous ideas about legal positivism, Hart strenuously denies that law should be seen as an imperative theory of law.  Hart’s interpretation of positivism is completely different to the accounts given by Bentham and Austin. This may be because society has changed dramatically since their time; as a result, contemporary legal positivism focuses less attention on a coercive picture of law. Hart made it clear that the only way to understand the true nature of law is to look at actual social practices that apply within our own communities. 
Law, in Hart’s analysis, is a system of rules, which our society constructs and transforms as time goes by. Legal rules are divisible into ‘primary rules’ and ‘secondary rules’.  Primary rules prohibited committing certain acts which would have jeopardised the close coexistence in our community (e.g. theft, murder etc.). However, as a society becomes more complex, there is obviously a need to change these primary rules, hence why Hart advocates secondary rules. Unlike primary rules, secondary rules do not generally impose duties, but usually confer power to adjudicate on breaches of primary rules, and to identify which rules are actually obligation rules.  For Hart, there are “two minimum conditions necessary and sufficient for the existence of a legal system”. They are that:
“those rules of behaviour which are valid according to the system’s ultimate criteria of validity must be generally obeyed, and its rule of recognition specifying the criteria of legal validity and its rules of change and adjudication must be effectively accepted as common public standards of officials behaviour by its official’s.” 
As already pointed out, Hart rejects Austin’s concept of rules as commands, and the notion that rules are phenomena that consist merely in externally observable activities or habit. Instead, Hart asks us to consider the social dimension of rules, namely the manner in which members of a society perceive the rule in question, and their attitude towards it. As we have seen Hart gives us in depth guidance on how we can best understand the nature of law.
Finally yet importantly, Hans Kelsen also provides his own view on what legal positivism stands for via his ‘pure theory of law’. Some have argued that Kelsen’s theory of law is complicated to understand hence why it has not been so influential.  In essence, his pure theory of law wants to define legal systems as ‘oughts’ or norms. [