Bob files a civil lawsuit agaist Rob. For simplicity, let's assume they both represent themselves.

At the hearing, Bob says: "Here is the evidence. Rob was wrong because of reason A, so he owes me money."

Rob replies: "Yes the evidence is true, but because of reason B reason A does not apply. I do not owe Bob anything."

Bob has nothing to add.

The judge proceeds making a judgment. Let's consider three alternatives:

  1. He simply agrees with Rob: reason B indeed negates reason A. No questions here.
  2. "Here is reason C why reason B in these circumstances does not actually negate A as Rob contends, so Rob still owns money to Bob."
  3. "Reason B does indeed negate reason A as Rob contends. However, notwithstanding with that, here is reason D why Rob is nevertheless at fault, so he owns money to Bob."

In adversarial common law jurisdictions, will judgements 2 or 3 be inappropriate for a judge to make? Are there rules in place that forbid judges from making judgements like either 2 or 3?

As a very simple example, the above reasons A, B and C can be instanced this way:

  • Bob's A: "Rob went on red light so he is liable"
  • Rob's B: "Yes I did, but that was right turn, which is allowed there"
  • Judge's C: "Right turn on red is indeed allowed there but not on Sundays when the incident happened, therefore Rob is liable".

Clearly, reason C was not raised by either party. Will the judge be allowed to not present it to Rob before delivering it in judgement?

This question has been induced by some statements made in feedback to this question:

By @phoog:

Courts generally cannot consider arguments that aren't raised by a party in the case.

By @Tim Lymington:

It would clearly be unfair (as phoog says) for the judge to base his judgment on his own research without giving either counsel a chance to consider it

So, how do those statements stand when judge, merely applying the law, can't help generating a new argument that neither of the parties thought of?

Closely related: If a judge constructs arguments for the prosecution in judgment is that grounds for appeal?

  • 1
    It's really just the same as a referee in sports competitions - they can't get directly involved in the game either.
    – MSalters
    Feb 11, 2019 at 8:03
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    @MSalters that analogy breaks down fairly quickly if you consider the progress of the game to be analogous to matters of fact and the rules of the game to be analogous to law. Players do not generally argue with the referee about what the rules of the game mean or how they are to be interpreted, but parties arguing before a judge do.
    – phoog
    Feb 11, 2019 at 16:08
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    The answer is different in inquisitorial civil law jurisdictions and adversarial common law jurisdictions to some extent, and the question doesn't specify the jurisdiction so it is har to answer. There is no doubt that a judge can do so in an inquisitorial system. The question is less obvious in an adversarial one.
    – ohwilleke
    Feb 12, 2019 at 1:28
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    @ohwilleke Thanks for this point. Let's assume adversarial common law jurisdiction.
    – Greendrake
    Feb 12, 2019 at 1:34

1 Answer 1



Deciding a case on a basis the parties have not raised is a denial of natural justice (or procedural fairness) and invalid.

The reason is very simple, the parties have not had the opportunity to produce evidence or make submissions about C or D that might have changed the judge’s mind about them. Notwithstanding, to successfully appeal, the aggrieved party must show there were arguments that could have been raised which could reasonably have altered the outcome.

That said, it’s the judge’s courtroom and they can say “That’s interesting but what about C and D?” and then the parties can make submissions about them. They do have to be circumspect and make sure that they do not become one party’s advocate - one party might be well aware of C and D and don’t want them brought up because they damage their case and they are hoping the other party misses that - and then the bloody judge come charging in with his bloody duty to wider interests of justice.

Non-judicial decision makers like arbitrators, adjudicators and other tribunals need to be even more circumspect because they generally don’t have a duty to anyone but the parties.

Unlike in civil law systems, the role of the judge is to decide the dispute between the parties as a referee, not to determine some objective”truth” as an investigator.

To keep things simple: if the plaintiff contends that the light was red and the defendant contends the light was green then, assuming there is no evidence opening the possibility, it is not open to the judge to find that the light was amber. Similarly, if the parties agree that red means go and green means stop, it is not the judge's role to tell the parties they are wrong (I'm sure questions would be asked but if the parties are adamant ...): since there is no dispute over this issue the judge would be wrong to agitate one.

Now, a judge is free to apply the law that was argued as a whole - if arguments centred on Section 14 of the Relevant Act 1875 but Section 15 is applicable and germane the judge is not wrong for applying Section 15. However, they are on shakier ground if the bring in Other Slightly Relevant Act 1956.

  • 1
    "assuming there is no evidence opening the possibility, it is not open to the judge to find that the light was amber." And if a witness claims that the defendant was drunk, but the defendant didn't present any rebuttal because being drunk was irrelevant to the cause of action presented, it would be unfair for the judge to rule on some cause of action that wasn't presented by the plaintiff for which the defendant being drunk is relevant. The defendant isn't obligated to present a defense against every possible claim imaginable, only the ones being asserted. Feb 11, 2019 at 23:03
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    I would disagree. While a party may not argue a point not raised on appeal unless one of the parties or the judge raises it, usually a judge can reach a legal conclusion not offered by either party even in an adversarial common law system, and also on appeal a trial court ruling will be upheld if there is any legal theory upon which the conclusion could be correct, even if the reasoning for the result actually given by the judge is wrong, even if not party argued it. The modern rule is also to allow a judge to grant relief not asked for originally by a party if it is not a default judgment.
    – ohwilleke
    Feb 12, 2019 at 1:32
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    If a judge grants judgment on a ground not raised by either party, either party may dispute that reasoning in a post-trial motion for a new trial or for reconsideration, so it does not violate natural justice (at least in a civil case, the analysis is more rigid in a criminal prosecution).
    – ohwilleke
    Feb 12, 2019 at 1:33
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    "Non-judicial decision makers like arbitrators, adjudicators and other tribunals need to be even more circumspect because they generally don’t have a duty to anyone but the parties." Arbitration awards are generally upheld even if the arbitrator is definitely incorrect about the law and usually aren't subject to appeal of any kind.
    – ohwilleke
    Feb 12, 2019 at 1:37
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    Judges in appellate courts routinely rule for reasons advanced very specifically by either party. I've seen this happen several times in the last few years alone. For example, in a case where a party put no case law in an appellate brief and the court ruled based upon a precedent decided only after oral arguments were complete found by a law clerk for a judge and not argued by either party (a motion for reconsideration was brought as a result and denied).
    – ohwilleke
    Feb 12, 2019 at 1:40

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