Philosophy of Law Spring 2024

Hart on Judges


Hart’s primary aim is to defend what he calls the separation of law and morality. This holds that the question “is this the law?” is a different question than “is this morally good?” Hart agrees with Bentham, Austin, and Holmes that the two questions should be kept separate.

This is his chief reply to Fuller.

The article considers two challenges to this position.

One turns on the fact that statutes and past court decisions sometimes do not have an exact, determinate application to particular cases. Critics of the separation of law and morality think that the solution to the problem of indeterminacy lies in including considerations of how the law ought to be as a part of the law. If so, then answering the question “what is the law?” sometimes requires answering the question “what should the law be?,” contrary to Hart’s view that the two questions are completely separate.

The other challenge comes from the experience of a society with immoral laws: Nazi Germany. Critics such as Gustav Radbruch allege that a belief in the separation of law and morality led people to fail to criticize Nazi law on moral grounds. The post-war courts in Germany seem to have taken this lesson to heart by refusing to recognize the validity of a law passed during the Nazi period that they deemed immoral.


Suppose that we have a statute that forbids vehicles in the park. We know that this rules out driving a car through the park. But what about a wheelchair? If the statute and past court decisions do not say anything about wheelchairs, how is a judge supposed to apply the rule when the police try to fine someone for driving a wheelchair through the park?1

Some scholars believe that judges who sincerely try to separate the questions “what is the law?” and “what ought the law be?” make bad decisions. As they see it, these judges try to make their decisions without any consideration of what would make sense. Instead, they grab the statutes and past court decisions and look for any way of applying these materials from the past to the case before them. This is a criticism leveled at what are called “formalists.” Formalists held that judges can use the law to settle any case they might hear. Furthermore, they held that this could be accomplished by applying logic to legal resources like statutes and past court decisions; nothing else was needed.

How might formalist judges decide the vehicles in the park case? They could see that all past cases have been about things that are normally used on land, have four wheels, and are capable of transporting a person. If they took these features to indicate what counts as a vehicle for the purposes of the statute, they would say that helicopters do not count as vehicles while wheelchairs do. Allowing helicopter landings in the park and banning wheelchairs doesn’t make much sense, but, the critics say, that’s what you can get if you insist that judges think like formalists and refuse to think about questions such as “what would make sense here?” The realists, such as Holmes and Frank, were especially focused on attacking formalism.

Hart cares about this because it appears that you could make the same point about his theory. If law is made up of rules, then judges should apply the rules to the facts of the cases before them and do nothing else. But that looks unrealistic here since the rules do not determine an answer. Worse, if you try to force an answer out of them, you can wind up with one that does not make any sense.

Hart has two chief things to say about this line of thinking (Hart 1958, 614–15).

First, he takes a shot at the realists for exaggerating the extent to which statutes and precedents are indeterminate. Even if some applications of a law are unclear or “in the penumbra,” it does not follow that this is generally true. Most laws have quite clear application which is why it is pretty easy for us to follow them.

This strikes me as a fine point, but I have to confess that I am not sure about how it bears on the question of whether it is desirable to separate law and morality or not. It shows that you can get by with the separation of law and morality in most cases. But the critics said you cannot do so for some cases, namely, the indeterminate ones.2

The second thing Hart says is that it would be clearer to simply admit that judges are making law when they decide cases on the basis of indeterminate statutes and precedents. As Hart sees it, what the critics are doing is pointing out that there are bad methods judges could use to make law. That is easily expressed using the distinction between law and morality: what the law is is one thing, what makes the law good or bad is another. By contrast, the alleged merger of law and morality is, in his opinion, murky.

I sympathize with what Hart is saying. But, at the same time, I think we should pay attention to the reasons why people are reluctant to embrace this. Think about that before class: what would be bad about a judge making the law? In particular, think about what it would be like to be one of the parties to the case being decided.

Conflicts Between Law and Morality

If law and morality are completely separate, then there can be valid laws that are morally bad and should not be obeyed. Hart agrees with Austin and Bentham’s opinion that if laws reach “a certain degree of iniquity then there would be a plain moral obligation to resist them and to withhold obedience” (Hart 1958, 616–17).

Their opponents maintain that the belief in a separation of law and morality has the opposite effect. They think that people who believe that law and morality are distinct think that moral criticisms of the law are inappropriate. The fourth section of Hart’s article contains a discussion of the views of a German scholar who repudiated his former endorsement of the separation of law and morality: Gustav Radbruch. Specifically, Hart discusses a case in which a court rejected a defense of having acted according to the law during the Nazi period on the grounds that the law in question was immoral and so not a genuine law.

Hart thinks this was a mistake. The Nazi law was bad law, but it was still valid law. So the only alternatives, in his opinion, were either to accept the woman’s defense or to punish her under a retrospective (or ex post facto) law.

Hart makes it clear that he thinks there would be a significant cost to punishment under retrospective law. How can it be fair to punish people on the basis of laws made after they did the things for which they are punished? His point is only that this is what the court was doing, in fact, and that it would have been better to acknowledge this explicitly.

That sounds right for an ordinary citizen. But how does it work for a judge? Say I am a judge who is asked to apply a grossly immoral law. And suppose I have been convinced by Hart, Austin, and Bentham, that law and morality are distinct. What should I do?

I could say “this is the law, but it is grossly immoral so I am going to follow Austin and Bentham’s advice and resist applying it.” Or I could say “this is grossly immoral, but it is the law so I am going to do something grossly immoral and apply it as it stands.”

Neither option sounds great.

I think that is part of the appeal of some sort of merger between law and morality. If law and morality were not separate, a judge would have a third option: “this statute is too grossly immoral to be part of the law so I am not going to apply it.” That spares the judge from either saying she is going to ignore the law or from saying she is going to ignore morality.

Of course, the fact that this would be a tidy solution if it were true does not make it true. But I think it helps to explain some of the attraction to the idea that there is some kind of union between law and morality.

Something like that seems to have been going on in the cases that Dworkin is going to describe next time. He’s going to say that some moral principles are part of the law. If he can make good on that, perhaps this third option is available.

Main points

These are the things you should know or have an opinion about from today’s class.

  1. What are the advantages of separating law as it is from law as it ought to be?
  2. How does the vehicles in the park case suggest that laws are indeterminate?
  3. What happens in the Nazi law case.
  4. Judicial legislation and ex post facto punishment.


Hart, H. L. A. 1958. “Positivism and the Separation of Law and Morals.” Harvard Law Review 71 (4): 593–629.

  1. Here are a couple real examples of cases like this. First, in the UK, it is illegal for a vehicle to use a blue light as that is reserved for emergency vehicles. There is a question about whether bicycles count as “vehicles” and so whether it would be illegal for bicyclists to use blue lights. Second, there is a parking lot in Monrovia where “wheeled toys” are prohibited; it’s the opposite of Hart’s case. Sign prohibiting wheeled toys↩︎

  2. Another oddity is that the realists agreed with Hart that law and morality are two different things.↩︎