Wednesday, April 7, 2010

Legal reasoning 3: Rules versus principles

My fellow bloggers and I have been bogged down with marking and tutoring so we haven’t posted anything interesting in a few weeks (I happily acknowledge that legal reasoning is far from interesting for most people) but I have promises from some of them that we should get some new content up in the next few days.

Tim posed an interesting challenge to the possibility that courts create new law when they distinguish cases (see the comments to last weeks post on distinguishing). In thinking of my response I realized that a very useful legal reasoning post would be on the difference between rules and principles. Once again, this post is aimed at people interested in thinking about legal reasoning.

Rules and principles are both legal norms that tell us how a particular decision should be decided. Take the following example:

Rule: If a person stays on someone else’s land for an uninterrupted period of 30 years without force, stealth or permission but with the intention to be owner then that person becomes the owner of the land.

Principle: Property law should protect legal certainty.

Imagine that a decision arises in which a court is faced with a situation where someone has camped on land for 30 years believing that they were the owner without the real owner’s permission. Both the rule and the principle point towards the same outcome: the camper should be made the owner of the property. The rule requires that outcome since the camper has camped uninterrupted for 30 years without force, stealth or permission believing herself to be the owner. The principle also suggests the outcome since making the camper the owner would promote certainty since people would have already thought that she was the owner and by recognizing this the law generates more certainty.

So what then makes rules and principles different? Here I am just going to quote extensively from the legal philosopher Ronald Dworkin:

“The difference between legal principles and legal rules is a logical distinction. Both sets of standards point to a particular decision about legal obligation in particular circumstances, but they differ in the character of the direction they give. Rules are applicable in an all-or-nothing fashion. If the facts a rule stipulates are given, then either the rule is valid, in which case the answer it supplies must be accepted, or it is not, in which case it contributes nothing to the decision.

On the other hand, principles operate in a different way. Principles don’t operate in the all-or-nothing fashion that rules apply in. Principles are reasons for or against certain outcomes in a case but principles don’t necessitate an outcome.

If we return to the example I gave above. Although one of the principles of property law is to promote certainty there are many situations in which property law would enforce an outcome that doesn’t promote certainty. For instance, if I take your bike the court will still make me return that bike to you. This undermines legal certainty (everyone who saw me riding the bike would have thought the bike was mine). However, the principle of certainty was outweighed by other considerations. So, the principle of legal certainty is a reason for an outcome but that reason can be overcome by other reasons.

A famous example of the application of principles in legal reasoning is the case of Riggs v Palmer (made famous by Ronald Dworkin). In that case a New York court had to decide whether an heir named in his grandfather’s will could inherit under the will even though he killed his grandfather. The court admitted that the rules that applied to the case clearly established that the murderer could inherit. However, the court continued on to say ‘all laws as well as all contracts may be controlled in their operation and effect by general, fundamental maxims of the common law. No one shall be permitted to profit by his own fraud, or to take advantage of his own wrong… or to acquire property by his own crime.’ The principle is that “none shall profit from their own wrong.” On the basis of that principle the court decided that the murderer could not inherit from their grandfather.

This principle is not a rule. The principle in the example was a reason for the outcome that the court reached but it did not act as an all-or-nothing reason. In law there are countless examples of where we let people profit from their own wrongs. For example, if you are speeding to make some very profitable deal that will close soon and you knock a pedestrian on the way we will still let you keep the profits from the deal (although you may have to compensate the pedestrian). This is not because all of those instances where we do let people profit from their wrongs are exceptions to the general rule. Rather, courts have weighed various principles against each other and decided that the principle that ‘none should profit from their own wrong’ was outweighed by other principles.

Our law is composed of both rules and principles. Knowing the difference between them will help you make better arguments in court. If there is a rule that operates in your favour then you will tell the court that the rule applies and so the court shouldn’t even consider other principles. However, if you don’t want the rule to apply you may argue that the court should have regard to a host of principles that support overruling the rule. The court would then have to decide whether to apply the rule or overrule it in favour of some legal principles.

Dworkin: Nerdy but awesome.


  1. Thanks for spoiling it for me - I enjoyed reading Dworkin so much, the stuffed dog on my bed is called Dworkin but I'm afraid that I'll have to reconsider having seen the beast for what he is. Just kidding - we all know that a sharp mind is the sexiest thing to have bar none.

    And funny coincidence - was reciting een bloedige hand erft geen goedt just the other night, family politics you know.

    Good write :-)

  2. A useful distinction! Thanks. Is this where Mikhail Dworkin Fassbinder gets his middle name?

  3. Who is Mikhail Dworkin Fassbinder?