Recently, I said to a friend that I would find it deeply unpersuasive if a team made a case using the argument that homosexuality was immoral. She was surprised by this, and told me that many debaters from her institution quite liked being judged by me, because they thought that I would give credit to any argument, no matter how weird it was.
It is probably true that I am more receptive to novel arguments than the average debate judge. In fact, I often have to resist the temptation to reward an argument simply because it is novel and interesting. But I'd like to think that I'm not indifferent between (for instance) a well-explained, internally consistent argument based on liberal principles, and an equally well-explained, consistent argument based on fascist principles. So what gives?
Roughly speaking, good judges should act as intelligent, open-minded, neutral observers to an argument, willing to be persuaded by either side. If judges hold extreme or unusual views, or hold usual views with unusual intensity, they should try as hard as possible to leave those convictions at the door and listen to arguments with a more moderate mindset. They should be willing to have this internal monologue: "Much as I think that this argument is not persuasive, that is in part because my views on this matter are unusually intense (or unusually well-examined). Most reasonable people would be persuaded by this argument, and I shouldn't let the bad luck of encountering me as a judge disadvantage the team that made it."
However, that's not to say that judges should be tabula rasa, judging arguments based purely on their formal properties, devoid of moral intuitions, or assessments of whether a claim is persuasive. It may be that some debating formats operate like this; and it may be that some debaters enjoy being judged like this. (It takes all sorts to make a world.) But that's not how BP debating works - and not how it should work.
Here are a few reasons why: Firstly, almost no meaningful normative claims are purely logical. (Non-philosophers often overestimate what is logically provable; that is, what can be shown to follow from logical axioms.) If we are going to make meaningful normative claims in debates (e.g., "We should invade Iran if it is on the verge of acquiring nuclear weapons" or "We should provide for the sick, even when their illnesses result from their life choices) then we are going to need to start from more than pure logic. If all starting points are treated equally, then debaters will always be talking past one another. Debating will simply be a game of identifying an internally consistent ethical position that justifies your beliefs - no matter how morally repugnant that position is.
Second, there are plenty of logically valid arguments that are deeply unpersuasive. Consider the following two arguments:
1a. Saving innocent lives at no large cost to ourselves is always morally required.
1b. This policy will save innocent lives at no large cost to ourselves.
C: Therefore we should enact this policy.
2a. Causing the deaths of innocents is always morally required.
2b. Enacting our counter-proposal will cause the deaths of innocents.
C: Therefore we should enact our counter-proposal.
These two arguments are formally identical, but I can't see any way for a judge to remain neutral between the two without debating becoming some kind of bizarre performance art.
Third, having judges suppress all their moral intuitions makes the act of persuasion in debating utterly unlike the act of persuasion in any other context. British Parliamentary debating is not a purely formal activity like Chess or Go; it is meant to be a contest of skills that come from real deliberative contexts. (Thus the term, parliamentary debating.) That doesn't mean that it has to mimic those contexts in every particular; but it does have to distill enough of the essential details to be a contest of persuasive skill - and it's not clear at all what it means to persuade someone who has no starting intuitions.
So for debating to make sense as an activity, judges do need to be entitled to some moral starting point. Being a fair judge doesn't mean being neutral between all possible moral positions. What then should judges believe?
My thoughts on this are a bit more disorganised. I don't think anyone has yet written down, publicly, in the context of BP debating, what judges should believe (or, to be precise, act as though they believe, when judging debates).
So here it is: Judges should have a defeasible presumption in favour of a moderate liberal position on most ethical issues. I use "liberal", not in the sense meaning "left-wing", but rather in the sense that would describe most intelligent university-educated people in the countries that we call "liberal democracies". By "defeasible", I mean that the presumption could in principle be overcome by a persuasive argument, and that the judge should listen to such arguments with an open mind.
What does such a moderate liberal judge believe? Here's a sketch: That judge has a strong belief in the importance of certain kinds of human goods - freedom, happiness, life, etc - though not a full theory about how trade-offs between these goods should be made, or a precise conception of what the good life is. That judge has a moderate presumption in favour of democracy, free speech, and equal treatment. That judge holds a defeasible belief in Mill's harm principle; that is, insofar as an action affects just the actor, the judge has a presumption against government action. That judge believes that important moral questions should be resolved by reasoned deliberation, not appeals to unquestionable divine authority. This is because a good judge is an open-minded individual of the sort likely to think that debating is a worthwhile activity.
One important detail: A good judge does not think that the moral status of a policy is always and fully determined by its consequences, at least when we use 'consequences' in the narrow sense of meaning its effects on utility or human welfare. There aren't two types of arguments, "practical" and "principled". The belief that all that matters is the sum of the consequences - that is, weighing up the costs and benefits - is itself a moral principle, and a contestable one at that. Rather, the judge does hold a defeasible presumption that the (narrow) consequences of a policy are important, but also a defeasible presumption that other dimensions of a policy (whether it is honest, fair, rights-respecting, etc) are also important. (We may be able to use "consequences" in a richer sense that encompasses many of these concerns, but that is an argument for another day.) Like most intelligent persons who are not debaters, that judge is neither a full-fledged "consequentialist" nor a full-fledged "deontologist" - but could, in principle, be persuaded to either side by sustained and careful argument.
So there you have it: A very rough first sketch of what a good BP judge should believe, often playing fast and loose with technical terms in philosophy that deserve a more careful treatment. I certainly don't claim a monopoly on understanding what ethical starting point good judges should have; but I'm trying to elucidate a folk wisdom that I imagine many other experienced judges share to some degree. Maybe, for other debate circuits in other cultures, there are other appropriate starting points. Perhaps a debate circuit between Islamic scholars should have a very strong presumption in favour of the existence of God and the moral authority of the Koran. And I'd really like to see the judging guidelines for Medieval Theologian Parliamentary Debating. But debating as we know it has grown out of an Enlightenment tradition that also produced the rest of modern liberalism, so (at least to my understanding) that's where judges' presumptions should start.