Philosophy of Law Fall 2019

Dworkin on Hart


Hart maintains judges decide cases in one of two ways:

  1. They apply legal rules to the facts in the case before them.
  2. They exercise discretion and legislate, revising the rules to give an answer to the case before them.

Dworkin seeks to show that:

  1. Principles play a significant role in judicial decision making.
  2. Hart’s theory that the law is the union of primary and secondary rules cannot accommodate principles: principles are not rules themselves and they cannot be identified using a rule of recognition.

If he can do that, he will have shown that Hart’s theory is incomplete.

What are Principles?

Here are some examples of principles.

  1. No one should profit from their own wrongdoing.
  2. A court’s decisions should be consistent with those made by courts in the past.
  3. A law that improves the general welfare is better than one that does not.

Principles thus range over the topics of justice, the role of judicial precedents, and good policy.

In addition to examples, Dworkin gives us two abstract differences between principles and rules (Dworkin 1967, 25–27).

  1. Rules are all or nothing while principles are not.
  2. Principles have weight or importance while rules do not.

Hart’s Dilemma

Dworkin tries to show that Hart has to choose between saying that principles are part of the law or saying that they are not part of the law. Neither alternative is palatable for Hart and there is no third option, according to Dworkin.

We were quick with the first option, that principles are not part of the law. We did that because I know Hart thought the other option was better. He had drafted a response to Dworkin that was published in the postscript of the second edition of The Concept of Law (Hart [1961] 1994). While Hart’s remarks were incomplete, his comments all concerned the second option, so that’s where we concentrated our attention.

If Hart says that principles are part of the law, then he would have to show that there is a rule of recognition that we can use to identify the principles that are part of the law and distinguish them from the principles that are not part of the law. Dworkin denies that this can be done.

There could be a rule of recognition about statutes: we recognize them as law if they are passed by the legislature and signed by the executive. We could also have a rule for judicial precedents: we recognize past judicial rulings as part of the law that judges use to decide cases. But what feature of principles would we single out in a rule that we would then use to say “these principles are part of the law and those are not?” This is essentially Patrick’s question about customary law from last week.

You could say “our rule is that whatever principles are appropriate to a case are part of the law governing that case.” But, as Chloe pointed out, that’s a useless rule. The rule doesn’t tell us anything about which principles are or are not part of the law. A judge would have to determine what counts as appropriate to make that determination; the rule itself wouldn’t do anything.

It seems to me that Maddie was right about what Hart’s best answer would be. He should say that we can use the familiar rules of recognition such as “if a principle is in the Constitution, it is part of the law” or “if the Courts routinely use a principle, it is part of the law,” and so on. If a principle cannot meet any of those tests, it’s not part of the law.

What would Dworkin say in response? Things get a little muddied by Dworkin’s concession that principles have to have some institutional grounding in statutes or past court decisions. This is what Dworkin says:

if we were challenged to back up our claim that some principle is a principle of law, we would mention any prior cases in which that principle was cited, or figured in the argument. We would also mention any statute that seemed to exemplify that principle (even better if the principle was cited in the preamble of the statute, or in the committee reports or other legislative documents that accompanied it). Unless we could find some such institutional support, we would probably fail to make out our case, and the more support we found, the more weight we could claim for the principle. (Dworkin 1967, 41)

But it’s pretty clear that Dworkin thinks that identifying principles involves a lot more than looking backwards to find their institutional origin in a statute or judicial decision. Here is the next paragraph.

Yet we could not devise any formula for testing how much and what kind of institutional support is necessary to make a principle a legal principle, still less to fix its weight at a particular order of magnitude. We argue for a particular principle by grappling with a whole set of shifting, developing and interacting standards (themselves principles rather than rules) about institutional responsibility, statutory interpretation, the persuasive force of various sorts of precedent, the relation of all these to contemporary moral practices, and hosts of other such standards. We could not bolt all of these together into a single “rule,” even a complex one, and if we could the result would bear little relation to Hart’s picture of a rule of recognition (Dworkin 1967, 41)

At the end of the day, Dworkin and Hart approach principles from two different directions. Dworkin thinks that the origins of principles are largely irrelevant to judges who apply them; it’s their substance, specifically their appropriateness, that matters. For Hart, it’s the other way around: laws are determined by their origins. For Hart, a law is a rule that comes from a source that can make laws, no matter how stupid the rule is. For Dworkin, a principle has to make sense, no matter what its source is or even if it has no identifiable source at all.

I’m not sure what I think. Some years I think that Dworkin has the advantage. Other years, I think Hart is coming out ahead or, at least, not behind. This year, I think a significant part of the class thought Hart was easily ahead, which I find interesting.

Two Points About Judicial Legislation

One point I meant to make, but failed to do so, concerns what appears to me to be a mismatch between cases like the one about the vehicles in the park and principles as a solution. Is there a principle that tells us what the right answer to the vehicles case is? Maybe if we take “principle” to mean “policy consideration” there is. But I wonder if there are always clear social advantages from deciding a case one way or the other. If not, bringing principles into the law won’t be enough to show that there is no need for judges to legislate in at least some cases.

My second point did come up at the very end. It is about retrospective or ex post facto legislation. What we said last time is that judicial legislation is bad because it means someone gets fined or punished for doing something that was not clearly against the law when it was done.

Would adding principles to the law help? The idea is supposed to be that the principles are already part of the law, so when judges make their decisions they are appealing to what is in the law rather than changing the law. But I’m not sure that this works. Since it is hard to tell how principles are weighed against one another, even according to Dworkin, it seems to me quite unlikely that an average citizen would know which principles apply to which cases. But if you can’t figure out what the law is, how could it be fair to punish you for violating it? Isn’t that the real problem with ex post facto laws?

I am left with the disconcerting feeling that this is a problem that simply cannot be solved. We are always going to be liable for prosecution for violating laws that we could not have known about.

Ross on Customary Law and Principles

Ross asked what the difference between customary law and principles is. I have to confess that I don’t know the answer with certainty, but I have a pretty good guess.

Customary law is law because it is old. It’s established by custom or by the fact that it reflects the way things have been done for a long time.

Principles are part of the law because they are appropriate. Their age is inessential.

The two categories will overlap quite often and positivists try to handle them both in similar ways. So, for our purposes, the distinction isn’t very important. But that’s how I think it should be drawn.

Key concepts

  1. Principles vs. rules
  2. Why it seems difficult to formulate a rule of recognition that could include principles
  3. The problem of ex post facto (or retrospective) legislation for both views


Dworkin, Ronald. 1967. “The Model of Rules.” University of Chicago Law Review 35 (1): 14–46.
Hart, H. L. A. (1961) 1994. The Concept of Law. 2nd ed. Oxford: Clarendon Press.