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Types of Legal Argument (philosophicaldisquisitions.blogspot.com)
102 points by objections 8 months ago | hide | past | favorite | 20 comments

The article explains why it's simplistic to think of legal argument as pure maths-style logical deduction. This goes back at least to Oliver Wendell Holmes (US supreme court justice from 1902), who made fun of those who treated a dissenting judgement "as if it meant simply that one side or the other were not doing their sums right, and if they would take more trouble, agreement inevitably would come."

Holmes said that law should be seen as induction, not deduction. Induction involves pattern matching, analogizing, and so on. I think that at least the first 4 of the 5 types of argument described in the article can be thought of as types of induction.

Holmes also said that the law consists of nothing more than prediction of what courts will do. And he described the development of the law in language that would make any Machine Learning person think of nearest neighbour classification: "The growth of the law is very apt to take place in this way: two widely different cases suggest a general distinction, which is a clear one when stated broadly. But as new cases cluster around the opposite poles, and begin to approach each other [...] at last a mathematical line is arrived at by the contact of contrary decisions."

It seems to me that the legal theory of Holmes, and the modern practice of machine learning, are remarkably similar. They're both about prediction based on experience / datasets. Shameless plug: I've written a (free!) book about it, "On the path to AI: Law’s prophecies and the conceptual foundations of the machine learning age".


I had the impression it was logic until the point where people talked about a priory stuff.

Like, yes, you're guilty of X if you did A, B, and C.

Lawyers then argue if it was really A and B and C. Was it really with intention etc.

Since the arguing parties weren't at the crime scene when it happened, they have quite a bit of wiggle room.

A few years back, I had a co-worker that was hostile to me. I won't go into the details why there's that hostility, but what happened was this:

- In the middle of a (chat) conversation that was going nowhere about a certain issue, he told me that I'm "difficult to talk to."

- I replied, "I can say the same thing to you."

This co-worker then complained to management, that I was being a bully and disrespectful. I provided the chat logs showing that the initial statement ("I'm difficult to talk to") was unprovoked, and I was civil all throughout our chat.

But this experience led me to wonder if there are legal concepts that I could have invoked in my defense.

The article mentions someone punching in the face.

What if this is the scenario: A punches B in the face. B punches A, as retribution. The physical and emotional damage to both parties are equal in nature. But A sues B for assault.

Will the case be dismissed? on what legal grounds? What are the applicable legal principles?

Provocation is a thing, e.g. reducing murder to manslaughter or 2nd / 3rd degree murder if the victim provoked the attacker first somehow.

Self-defense is a thing, it's sometimes reasonable to attack a person before or while they are attacking you.

Retribution is not a legitimate grounds for assault, that's what the justice system is for.

Your example is light on details, but if it's just retribution without an element of provocation / self defense (e.g. B punches A one year after A punches B), then there wouldn't be a reason to dismiss such a case.

As for your conversation, one principle in any organization is to remain polite and professional at all times, even (and especially) when other people are not. If a conversation is "going nowhere", telling the other person that they are "difficult to talk to" could be a legitimate observation or constructive feedback. Management have no interest in analyzing the rights and wrongs of such situations, they only care about who acted professionally, and not about the order and reasons behind such behavior.

"You're difficult to talk to" is not a hostile statement. It's also what you say to someone after they're being difficult, not before. I don't think the reply of "no, you" would be the problem.

And if somebody tells me I'm difficult to talk to (which has happened about particular subjects with particular people), my response is not to look for something to accuse them of so they don't win. I either ask why, or if I know I'm being reasonable, terminate the conversation.

Talking to somebody who is constantly trying to equalize their position with you is fine usually, but trying to criticize, teach, or suggest a different approach to them is impossible. They don't listen, immediately get angry, and try to find something they can criticize about you (even if they don't really mean it.) I think it's a sign of abuse.

Many legal systems allow limited retribution, if it can be seen as proportional to self-defense.

That said, there's an overarching idea that one shouldn't try to "get even" by lowering oneself to the other person's level. Proportionality as a legal concept makes it legal to defend yourself, but illegal to escalate the threat.

E.g. one can use fists against fists, but if B stabs A to death, it will be hard to claim it was in self defense, since there is no obvious proof that A was looking to murder B by punching B to death.

If it is possible to refrain from violence and use the justice system to replace it (by having B press charges against A), then that ought to be a more civil outcome.

One could argue that the reason to have a legal system is so that B does not have to go around preparing to punch back, but can spend her time doing more productive things and that is how we end up with a civil society, with a high level of productivity and freedom of expression, and a minimum level of violence.

Of course, if one person is physically stronger than another, then more tools are required to respond proportionally; tools that may make an accidental over-retaliation more likely.

While society prefers civil solutions to physical conflicts, civil solutions take longer, often require social, organizational and financial capital, and have less certainty in outcome. Society overall is better, but individuals are often not as well served.

The system is stacked in favour of the more powerful at every level, shocker.

I cannot imagine the police taking an interest in a case like that, let alone a DA prosecuting it, absent other factors making it politically important.

Clearly explained. Thanks!

Here is the answer for a typical state in the United States.

In a civil suit, a punch in the face typically results in a claim of battery (among other possibilities, such as assault). A battery is an “intentional tort” where a person intentionally causes a harmful or offensive contact with another person.

One defense to an intentional tort like battery is “self defense.” It varies from state to state, but generally a person may use reasonable force to defend against an offensive contact that he or she reasonably believes is about to happen, but the defense must be proportional.

So in your scenario, person A sues B for assault. If person A admits that he was the initial aggressor and the response was reasonable and proportional, the case may well be dismissed. If they do not directly admit it but the facts show they do admit show that the response was proportional as a matter of law, the case will also be dismissed.

If not, the case will continue to summary judgment. If, after discovery, no reasonable juror could find that the response was not reasonable and proportional (i.e., there is no genuine dispute of fact), then the court will find for person B. But if a reasonable juror could find that the response was not reasonable and proportional, the case will continue to trial.

(Both dismissal and summary judgment will only happen if person B moves for relief, but that almost always happens)

Obviously, person A’s attorney is going to know these rules going in, and they are going to do their best to portray the facts in a way that the claim will survive motions to dismiss and for summary judgment and make it to trial.

Once you make it to trial, anything can happen, because it is in the hands of the jurors.

After the jurors render a verdict, the court will review that verdict to determine again if the prevailing party presented sufficient evidence for a reasonable juror to find in their favor. The court will also evaluate whether any errors occurred in the trial that warrant a new trial. Then the losing party has an opportunity to appeal those and other rulings of the court.

The legal concept you're describing is "comparative responsibility"[1]:

> [A] doctrine of tort law that compares the fault of each party in a lawsuit for a single injury.

> Comparative responsibility divides the fault among parties by percentages, and then accordingly divides the money awarded to the plaintiff. The plaintiff may only recover the percentage of the damages he is not at fault for. If a plaintiff is found to be 25% at fault, he can recover only 75% of his damages.

The answer to your hypothetical is, of course, it depends! The "United States" section of the wikipedia article has a good outline of the different ways states implement the doctrine. It boils down to: sometimes it can be a complete bar to recovery if the victim is at all responsible, sometimes there's a threshold level of responsibility where it will bar recovery, and sometimes it's a percentage reduction as described in the example above.


In conceal carry weapon courses in the USA, there's three factors that stand out in a self defense situation. Ability, Opportunity, and Jeopardy. Is the person capable of hurting you, can he do it at a given moment, and is he doing it or about to do it? With few exceptions, those who shoot in self defense and abide by these three factors, don't go to prison.

You can watch some Massad Ayoob videos on the topic, though they are pretty old.

I would not seen "difficult to talk to" as punch or uncivil, at least not in general case. Specifically in the context of conversation that goes nowhere. It is (slight) criticism and simultaneously it is opening meta discussion about "why is this conversation failing". But criticism is allowed in polite company.

No A could sue B for whatever damages they sustained, but also B could turn around and sue A. If their damages were exactly the same then they would both end up in the same position they were originally, minus lawyer fees, so there isn't much motivation for either of them to do this.

I've been dabbling in expert systems (aka rules engines) for the last few years. See CLIPs and Rete algo in your language of choice.

This, combined with exposure to KNN over TF-IDF (either live indexes like Elasticsearch under the hood or GiST over trigrams in Postgres or custom trained models), allowed me to discover a kind of "ratcheting" of knowledge.

If the I/O of the program is like an interview with a client, then it's possible to have a "topic stack" where each frame represents a volley in that conversation. I think chatbots also go deep on "dialog engines" like this (see RavenClaw).

For each fact being input, it's possible to check all the policies (rules) that might apply in a declarative way where the developer doesn't need to care about order. Rete takes care of performance concerns, but it's not horizontally scalable (which doesn't really matter IMHO).

Then, for the same stack frame, checking what all other facts are by doing that light KNN to see which other fact patterns were similar, and computing the rule matching on those selectively. This is like making analogies to case law.

Rinse and repeat that flow until some kind of solution is found/suggested/validated by the user, etc. See SHYSTER paper which covered this approach in the 90s.

A very insightful and thought-provoking summary of the traditions and methods of legal reasoning. Makes you realise how law, philosophy, logic, policy, societal traditions are tightly integrated in what we assume to be "independent" judicial systems. There's some spirit and philosophy behind the text of the law, there is morality involved with each particular act of the suspected person, and matching a particular case to a particular rule is a hard problem.

This article is the type of tripe they teach us in law school that has no real world application.

I get the point the author is trying to make: that you can distill argument down to its essence, and that you should.

What the argument fails to take into account (to name two) is:

1. We have “splits of authority.” One court says the law is Y and one court says the law is X. Now it’s roses are red in this jurisdiction and pink in another. The whole thing goes off the rails.

Argue your point as best you can and hope!

2. Many statutory schemes have become insanely complex so as to make distilling arguments to their essence nearly impossible. Additionally, each piece of complexity is another opportunity for courts to diverge in interpretation (see point 1).

To be sure, the classic common law claims —- murder, robbery, larceny, battery, etc — are amenable to this type of distillation, but that’s so little of what the practice of law is anymore.

Students get an education like described in the article, and then they come out woefully unprepared for the real world.

The article does address the two points you mention, and also addresses contractual arguments and examples.

> Argue your point as best you can and hope!

This sounds like a recipe for distress. Isn't the utility of the idea that whatever argument you face, whatever tort or contract or criminal allegation you are fighting for, your best will be better if you understand the logical premise of the argument and the way it is carried forward?

What do you suggest the students learn in addition to or instead of this?

> What do you suggest the students learn in addition to or instead of this?

Two things:

1. Many people don't start from a premise of: "Let's find out what The Law requires of us and we'll proceed accordingly, out of a sense of duty, loyalty, and obedience."

Instead, to a first approximation, their starting point is: "I don't give a [hoot] about The Law except pragmatically — I want to do X, so I want to know: (i) under The Law, what pain could others inflict on me if I were in fact to do X, and (ii) by what means could I prevent, or at least mitigate, such an outcome?"

2. Weather forecasting is the best analogy I've come up with to describe legal analysis: You have to make a best guess about how various "energy sources" — litigants; legislatures; courts; armed camps — will interact at a given place and time.

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