To what extent are legal positivists and natural law theorists disagreeing and to what extent are they merely speaking past each other? The battle between legal positivist and natural law theorists has been going on for generations, and will no doubts continue to go on. The main reason for this is that on the surface both these theories appear to be at opposite ends, one claims that in order for an act or judgment (i.e. law) to be valid there must be some moral principle (legal validity requires with it a moral principle), while the other claims that morals are not important in the creation of laws, as long as a valid procedure is used (legal validity is not dependent on morals but is rather dependent on the few who are capable of making law and the procedure which is used to make the law). This is just on the surface though, both these theories are like opposite ends of poles yet they are of the same pole, meaning that despite being different the fundamental principles are very similar. I will start off by outlining the two theories. I will then move onto stating the differences between these two theories, which seem to be obviously present. Then comes the difficult part of establishing the similarities i.e., instances where they do actually talk about the same principles, and that on the basis of it all the application of both the theories seem to be very similar, in order to do this effectively a deeper understanding of both the theories must be developed. Finally I will also hope to evaluate a very interesting article by Deryck Beyleved and Roger Brownsword  which attempts to link in legal positivism and natural law theory and claims that there is no practical difference between them the difference is just theoretical.
To begin with what is natural law? This is the first question one needs to answer in order to be able to comment on the similarities and differences it has with legal positivism. Natural law although consistent has had many different schools of thoughts but the basic principle in the end is that laws in order to be valid must be moral, in other words the famous phrase “An unjust law is no law at all”  . Legal positivism on the other hand states that there is no connection between the validity of law and ethics or morals, they see law as being made by lawmakers of a community and that is what law is. So the application of this can perhaps be used to say for example there is an Act of Parliament which wishes to ban all Birmingham University Law students from eating chocolate, for Natural law theorists this would not classify as a valid law because it is seen as discriminatory to Birmingham University law students and therefore considered immoral. On the other hand for the Legal positivist this law although immoral and discriminatory is still nonetheless a valid law as it has been passed through the Parliament and therefore has satisfied all the stages which are required to be law and so for legal positivist all the Birmingham Law students must not eat chocolate in order to (according to Austin) avoid negative sanctions.
Legal positivism is a fairly new concept compared to natural law theory which can be traced back to the ancient world. One of the first people to write about the concept of legal positivism was Bentham but it was not till John Austin’s version of legal positivism  that the theory came into notice. Bentham proposed that there is a difference between what the law in practice was and between what law ought to be and he stated that we as a society should move away from law as it ought to be and move towards law as it is in practice he termed this expository jurisprudence and the law as it ought to be as censorial jurisprudence. John Austin, who was followers of Bentham, furthered the claims of legal positivism in his book  ; Austin claimed that “laws “properly so called” are commands of a sovereign”  . A positive law according to Austin is a command, accompanied with a sanction, set by a superior to a political inferior. Application of this can be a simple law for example the infliction of grievous bodily harm is contrary to section 20 of Offences Against the Person Act 1861, here there is a command which states that one must not inflict grievous bodily harm onto another person, and if this is not complied with there is a sanction in that the person could go to jail, this was law passed through Parliament and assented by the Queen who is seen as the political superior and is applicable to everyone who is in Great Britain the political inferior.
Blackstone, a natural theorist, on the other hand claimed laws of God “are superior in obligation to all other laws; that no human laws are of no validity if contrary to them”  . This theory is completely opposite to that of Austin in that Blackstone’s theory claims that laws made by “god” (even though controversial we will take in this case “god” to mean moral principles of a given society) should prevail over all other laws basically meaning that moral principles should be upheld even if they do contradict the positive law. Put it simply it means that in order for there to be legal validity there must be a sense of moral obligation. Austin does not have a problem with the fact that the human laws be compatible with that of the divine law but what he does have a problem is with the fact that if Blackstone means that no human law will be obligatory if it is contrary to the divine law. He states that this cannot take place in reality as even the laws which are opposed to the will of “God” have been and will continue to be enforced as laws by individual tribunals. Austin contrary to Blackstone believes that legal validity is not dependent upon moral obligation.
In Answer to Blackstone Hart says that if what Blackstone is saying is that laws should conform to the divine law then Hart assents to it, or even if he means that human lawgivers are obliged by the divine law and if they do not follow this obligation they will be punished Hart assents to that theory as well.  But what Hart interpreted by this is “that no human law which conflicts with the Divine law is obligatory or binding; in other words that no human law which conflicts with the Divine law is a lawâ€¦”  This demonstrates the differences which are present in both the theories what Hart is trying to state here is simply that if the natural law theorists state that law makers should conform to the divine law then that is acceptable theory but to state that laws should not conflict with the Divine law is not an acceptable concept of law.
Austin claimed that the divine law is known through the principle of utility and “if the general good which would follow submission â€¦outweigh the general good which would follow resistanceâ€¦the subjects are bound religiously to pay it habitual obedience”  . This means that we have an obligation to obey positive laws; Austin is not sure whether this is because it is a behavioural tendency or it is because general utility the conformity to positive law is nonetheless morally desirable. He then goes on to point out the fact that this moral obligation to obey positive law can only be broken if it is so wrong that the good which is gained from resisting to follow the positive law is greater then the punishment of not following the positive law. What then needs to be established is the positive laws which it is not our duty to obey. Until the point is reached where the resistance to law becomes acceptable, it is our duty to obey the positive law. Both Austin and Bentham insisted that law should be distinguished between law as it is and law as it ought to be, this is one of the most important distinction for the orthodox positive law theorists, as they claimed that the law as it is, is the only valid law and law as it ought to be is not valid until it becomes the law as it is. For example the Children’s Rights Bill  which is currently going through the Parliament, and the prohibition placed on sale of children, child prostitution and child pornography, is morally desirable and so it is the law as it ought to be, according to Austin and Bentham it is still not law as it is because it has not attained Royal Assent, although this is likely to be covered in some previous Acts of Parliament for example the Sexual Offences Act 2003.
The fact that positivist theorists such as Austin and Bentham both recognise that positive laws although must at all times be followed, they also provide for situations where it is permitted to not blindly follow the law. This view is very similar to that of natural theorists, although the content of each theory may differ between them two. Both the school of thoughts believe that the “positive laws of a reasonably enlightened legal system are morally binding to the extent that are not incompatible with the favoured set” 
Austin theory however was seen as flawed and somewhat lacking in its adequacy and application to a real working complex community away from that of a simple society outlined by Austin, for example his use of the word of a sovereign caused some problems: USA who is the legal sovereign? Hart’s aim then was to develop further on Austin’s concept of legal validity and to modernize the concept so that it can be applicable to complex societies which are existent today  . Hart replaced Austin’s theory of law as general orders backed by threats and given by one generally obeyed to a system of rules “where a secondary rule of recognition is accepted and used for the identification of primary rules of obligation”  . Hart does not however abandon the principle which was established originally by Bentham and further developed by Austin that legal validity has nothing to do with moral obligations. Hart claimed that laws must also be “efficacious” in the sense that they belong to the system which is habitually obeyed. Hart claimed that legal validity implies a form of social duty but not a moral duty. He argues that if we were to follow only laws which are morally justifiable then we are essentially ignoring some complex laws which are needed for the smooth governing of the society. Hart then goes on to state in his book that in order for something to be legally valid is not a question of obedience but rather in the end it all comes down to “moral scrutiny” meaning moral values. What Hart is perhaps trying to say here (and I may be putting words in his mouth but this is my understanding) is that in the end a law will not be valid just because there is an obligation to obey it in order for it to be valid there must also be a moral duty to obey it.
If this is what Hart means then essentially there doesn’t seem to be much of a difference between his theory and that of natural theorists. They are both essentially stating that laws which are not morally reprehensible impose duties. Although Hart does not expressly claim this position in his concept of law, he does state that if a law is really bad, then even though it is a valid law it must not be obeyed. According to Hart then if a law is too “iniquitous”, it will not create a duty.
Let’s now examine the fundamental claim by positivist lawyers; they all state that legal validity is not relevant to moral duty or obligation, if this is the case then why is Hart claiming that if a law is wicked then they do not bind us to perform specific actions. Does that mean that if a law is not too wicked then we must obey it? If this can be assumed from Hart’s theory then one of the essential part for there to be a valid law is that it must not be wicked this makes positive law very similar to natural law which claims that morally wrong laws are not valid, and a wicked law will obviously be immoral.
Hart would have not claimed that “iniquitous” laws must not be obeyed when what he was trying to prove or rather show was that there is not connection with law and morals and that whatever the law is, whether morally right or wrong, it must be obeyed. Hart in his later work entitled “Are there any natural rights” stated that non-iniquitous laws impose duties on us just because they are laws. He states “officials should have the authority to enforce obedience and make further rules, and this will create a structure of legal rights and duties, but the moral obligation to obey the rules in such circumstances is due to the co-operating members of the society, and they have the correlative moral right to obedience”  . This suggests that we obey the law because we owe it to those in the society which do obey the law, and thus obedience to a rule becomes obligatory, it is not because of moral character of the rule that it becomes obligatory but rather it is because it is a positive law that it creates obligation. This principles seems to be contradictory to that of natural law theorists, perhaps what Hart was trying to do is to establish a distinct difference between positivist law and natural law.
David Lyon criticised Hart’s theory by stating “we have no reason that those who are enslavedâ€¦still subject to lawâ€¦are beneficiaries of the system. If they are not beneficiaries then the argument for fairness does not apply.”  It seems like Lyon seems to have misinterpreted Hart’s theory as what Hart claimed was that no one according to his theory is bound by iniquitous law and that if a person is victimised to such an extent then he is under no obligation to obey the laws of that system. Hart’s proposal is only applicable to laws which are not iniquitous and not incompatible with the fundamental moral principles.
So far we have looked at the way in which positive law was developed we have also looked at some of the natural law theories and how they are similar in certain ways but distinct in others, but now we must consider the origins of natural law theories. Natural law theory can be traced all the way back to Aristotle, his theory was known as classical natural theory and was very orthodox compared to modern day natural theories, like the one developed by Finnis.
Aristotle developed his theory in ancient Greece, it was developed in a society where law was not passed for everyone but rather for just minority of those who were lower in the social chain, the vast majority were slave who had no rights at all and their whole social and legal existence was based upon their owners, further there was no attempt to create equal rights for all. In the ancient Greece the law was directed towards the ends rather then the means of human activity, meaning the ends of achieving an honourable and virtuous life. Aristotle’s theory of natural law (what the law commanded varied from place to place but what was by nature was the same everywhere) was not recognised and given proper credential which it deserved until Thomas Aquains brought it into our attention. Aquains stated that “[law] is nothing else then a rational ordering of things which concern the common good.” 
To explain his theory Aquains used the following example “All people, indeed, realize that it is right and true to act according to reason. And from this principle we may deduce as an immediate conclusion that debts must be repaid. This conclusion holds in the majority of cases. But it could happen in some particular case that it would be injurious, and therefore irrational, to repay a debt; if, for instance, the money repaid were used to make war against one’s own country”  this theory claims that although according to law we are obliged to do a certain thing, and if not doing that thing in a certain situation is seen as moral and doing the thing in the situation creates result which is so wrong that it is better to disobey the positive law then one should not be obliged in that situation to obey it. This theory although seems different from that of Hart is actually very similar in the sense that even Hart claims that if following the law creates an evil then one is not obliged to follow that law. However what seems to differ here is just the extent to which the law can be disobeyed. For Aquains the law can be disobeyed if it is just immoral, whereas for Hart the law can only be disobeyed if it is so immoral that following it would be obscene and create some grave evil. However flaws can be picked in Aquains theory.
The content of natural law consists of prescriptions and permissions which are very general and include the application of positive law. For example even Aquains stated that the rules which are incompatible with natural law, which are made into positive laws by human intervention come within ‘determination’ and come from “ordinances of reason or the common good, made by him who has care of the community and promulgated”  this shows that Aquains did not disregard positive laws and thought that positive laws were necessary and that it was not only laws made by God which were important but also laws made by human beings which are equally important. Thus what Austin is perhaps and certainly natural theorists are trying to state is that rules which are not inconsistent with natural laws become our duty to obey once they become positive laws. Obligation is obviously created for positive laws which are consistent with natural laws and in fact it is when these natural laws get transformed into positive laws that moral obligation is created. Further that this obligation to obey laws is not subject to any discrimination, meaning that the positive laws are obligatory upon all in any given society.
So far what has been outlined is the fact that despite being different on the surface both the theories claim very similar things. One of the main problems that was present was that positivist believed that in order for there to be legal validity the rule does not have to be a moral rule, but then once looked at in a deeper level we noticed that most major legal positivist (this includes Austin, Bentham and Hart) believe that if a law is fundamentally and morally wrong then there does not need to be a duty to follow the law. And the major disagreement that natural theorists had with legal positivist was that natural theorist’s believed that in order for there to be legal validity the rule must be a moral one, however as we have seen Aquains accepted that once a morally neutral rule has been enacted by the state, it is a “true” law and therefore rises legal obligations.
In his discussion of legal obligations John Finnis states that if a ruler uses his authority to “make stipulations against the common good, or against any of the basic principles of practical reasonableness, those stipulations lack the authority they would otherwise have by virtue of being his.”  Finnis is referring here to concern serious moral defects of the legal system. But what about laws which are not seriously immoral, what about laws which posses neutral reaction? For example laws on income tax differ widely in the sense that there are many people who believe that the people who earn more should be taxed more and people who earn less taxed less but there are also people who believe that the tax band should be equal for all income, how can morality decide the ceiling band for income tax, if we left it for natural law to decide this there would never be a satisfactory law in force. Perhaps this is the reason that natural lawyers state once such a decision has been made by enacting a positive law by the authority then this implies a duty.
Both Bentham and Austin allow this thesis presented by Finnis. As mentioned before both Bentham and Austin’s theory states that a positive law should be applied unless it is so harmful that the suffering caused by the breach is lesser then obeying the law itself. Put in simple words this means that we are obliged to obey laws because they are laws. This theory however requires justification which Bentham and Austin fail to provide. Hart is the first legal positivist to provide this justification he states “the principle involvedâ€¦is that when a number of persons restrict their liberty by certain rules in order to obtain benefits which could not otherwise be obtained, those who have gained by the submission of others to the rules are under an obligation to submit in their turn”  . What Hart is trying to state here is that we obey laws not just because they are laws but because by obeying laws we gain something, and law is also obeyed because we have gained something in return for others conformity to law.
Baker has argued: “… no structure is value-neutral; all social structures affect both what people get and also how they interact; that is, affect both end-results and processes. Any structure … shapes tastes and distributions, organizes the processes of realizing values, and embodies a concept of value and of man”  . Here, Baker is trying to state that positive law are a formality meaning that it is the procedure which makes the laws positive, however in order for there to be a positive law there must be some substance to the law and this substance is found in the form of natural laws and morals which have been made up over the generations by the community and which is continuously evolving. This suggests that in order for there to be law both cannot exists separately they must co-exist.
However it must also be noted here that legal positivism operates on the basis of a backward-looking theory which is basically that positive laws are based on past social conduct, legislations and case law, whereas natural law is based on changes in society and takes into account the developments in society. This was obviously clear by Robert Geoff’s speech in the case of Elliot v C  where despite strongly opposing the test of ‘recklessness’ for the purposes of Criminal Damages Act 1971, established by the House of Lords in R v Caldwell  and R v Lawrence  , he was forced to implement this test despite according to him it being morally wrong, this was because it was the law and therefore there was a duty as an authoritative figure to implement the law “as it is” and not the law as it “ought to be”. This basic example illustrates that positive law is unlike natural laws in that it does not demonstrate the views and opinions of the society as a whole and only demonstrates to some extent the laws of the past which may not be valid today.
One of the aims of legal positivism is the application of rules to all human beings i.e. equality. This is hard to be achieved by natural law theory which obviously takes into consideration the morals which differ widely. As Marx pointed out “they (human beings) would not be different individuals if they were not unequal”  and therefore one of the aims of law should be to provide stability and equality in unequal circumstances which the natural theory of law will find hard to provide but is easily provided by the legal positivist.
Hart pointed out that even legal positivism are bound by morals and that certain laws are made purely by taking morals into account. A clear example of this can be found in the vast majority of case laws. Judges make decisions based on their moral principles. An example of judges using morality to base their decision can be found in criminal law and when the judges are deciding on the sentence to be given they have to balance a lot of conflicting morals and come up with a sentence which does not put the society to any further harm, the victim and their family must also be given “justice” and the judges also have to take into account the criminal, in that they must have a way of obtaining a position in society “whose laws he has violated”  . This shows that one of the aims of laws is the upkeep of moral values which is not farfetched from the ideas presented by natural law theorists.
When it came to interpreting Nazi law regime the similarities as well as the differences between both the theories really stood out. Nazi law was seen as legally invalid and was also declared invalid following the World War II. The law enforcers under the Nazi Germany had to be punished and it would have seemed highly immoral if they were gone unpunished. However, a problem arose in the sense that the perpetrators claimed that they were just following the law and that they were under a legal obligation to follow the Nazi Germany Law, and because law cannot be retrospective it seemed that the perpetrators would go unpunished. The “Laws” which were followed by them were declared to be invalid as they contradicted the fundamental principles of morality. Hart justifies this and no doubt Austin as well as Bentham would also justify this decision. This demonstrates the application of what we have discussed thus far, that if a law is fundamentally morally wrong then declaring such law as invalid should not create sanctions.
However what must be noted here is the fact that it seems that throughout his article  Hart seems to distinguish Nazi Law and English law on the basis that the only difference present is the fact Nazis used the law to achieve ends which are horrible according to English law, this is a mistaken belief as it seems like Hart found no problem with the Nazi regime and saw the vile Nazi law as a valid law. Although this is not what Hart is stating it has been interpreted by many theorists in this way including Fuller.
Fuller in his critique of Hart  on the topic of Nazi law seems to interpret the law differently from that to Hart and criticises Hart’s theory for not being able to work effectively in emergency such as was present in after the World War II. As what Hart would have preferred would have been a retroactive statute, this would not work as in emergencies one does not have the time to pass statutes the situation in hand must be resolved as soon as possible.
This shows that despite the similarities present between legal positivism and natural law the way in which the theories interpret the law differs. But perhaps Fuller was being harsh on Hart, as reading the article it seems that Fuller was out to criticise Hart on every single point. He claimed that Hart would have liked a retroactive statute to be passed in post war Germany to tackle the issue of the morally wrong Nazi laws, yes perhaps it is true that Hart would have liked for there to be a retrospective law but it is also true that Hart also considered Judges to be an authority which makes positive laws and therefore the decisions passed by the Judges in Germany were laws. Credit should be given to Hart for bringing morality into positive laws and recognising that immoral laws are not laws.
Hart differentiates his theory of positive law with some natural law elements as has been seen, from that of pure natural theory by stating that natural law theories “attempt to push the argument much further andâ€¦assert that human beings are equally devoted to and united in their conception of aims other than that of survival, and these dictate a further necessary content to a legal system without which it would be pointless.”  . Hart then goes on to say that what natural law theorists have tended to do is ignore the differences between human beings which are obviously present, although he is more careful then Austin and Bentham not to exaggerate these, he states although human beings have this minimum purpose stated by natural theorists they also have other purposes which are too “conflicting and varyingâ€¦ (To an extent) that some fuller overlap of legal rules and moral standards is “necessary”  in this sense.
Deryck Beyleveld and Roger Brownsword  state that even if it can be found that the discussion between natural law and positive law is conceptually significant, the dispute is none the less trivial “from a practical point of view”. They provide two reasons for this argument “(1) Since neither natural-law theory nor positivism is tied to any specific ethical position there would be nothing in principle to prevent rival conceptual protagonists holding an identical view of ethics; in which case
(2) There would be no necessary practically significant disagreement between such conceptual rivals.” 
What is meant by the first of these justifications is that because no theory has an ethical point which needs to be