I am not a lawyer. This article contains no legal advice; I merely use legal metaphors to make epistemological arguments.

Philosopher Ayn Rand has likened the mind to a courtroom:

[T]o pronounce moral judgment is an enormous responsibility. To be a judge, one must possess an unimpeachable character; one need not be omniscient or infallible, and it is not an issue of errors of knowledge; one needs an unbreached integrity, that is, the absence of any indulgence in conscious, willful evil. Just as a judge in a court of law may err, when the evidence is inconclusive, but may not evade the evidence available, nor accept bribes, nor allow any personal feeling, emotion, desire or fear to obstruct his mind’s judgment of the facts of reality — so every rational person must maintain an equally strict and solemn integrity in the courtroom within his own mind, where the responsibility is more awesome than in a public tribunal, because he, the judge, is the only one to know when he has been impeached.

Through one of her fictional characters, she also likens certain actions to literal crimes (emphasis mine):

[T]o withhold your contempt from men’s vices is an act of moral counterfeiting, and to withhold your admiration from their virtues is an act of moral embezzlement—[...] to place any other concern higher than justice is to devaluate your moral currency and defraud the good in favor of the evil [...].

When a judge treats a woman favorably because she is beautiful, say, or accepts a bribe to exonerate a guilty man – or, worse, to imprison an innocent one – or, more generally, whenever he abandons consistent application of rational procedure to ensure some preconceived outcome, then he is not following proper, objective standards of justice. He is playing favorites. The same applies to a policeman who, in an effort to advance his career, doesn't ticket a powerful politician he pulled over. Such people are corrupt: they disregard the relevant evidence in favor of unrelated ideas; they let personal preference or ulterior motives override proper procedure.

More generally, people often play favorites with ideas. Some ideas are as appealing as beautiful women. A corrupt mind, by definition, disregards rational, objective standards for evaluating, accepting, and abandoning ideas, and plays favorites instead. For example, when someone disregards a criticism he should know to be true so that he can hold on to a more flattering or validating idea, he is being epistemologically corrupt. Epistemological corruption is a type of irrationality; a type of intellectual misconduct.

It is a lawyer's job to get the best deal possible for his client, even if he knows that his client broke the law. Conversely, the prosecution's job is to ensure that guilty people are punished. This division of labor works because there's a third party – the judge – to pronounce judgment.

A proper judge, both in law and in the realm of ideas, must be dispassionate and clinical in his evaluations. He cannot simultaneously be a lawyer for one of the competing sides or ideas – yet that is what many people allow themselves to become, turning the courtroom in their minds into a kangaroo court, where they are not bound by a code but act merely on whim.

 

In pursuit of truth, one should, ultimately, act neither as prosecution nor defense. One must act as a judge.

 

Consider how a proper judge is not swayed by public opinion. That would be arbitrary: he could just as well make the opposite decision if public opinion demanded it. But consider also how many people do let themselves be swayed by public opinion in the realm of ideas generally, completely unbothered by the fact that this is just as arbitrary.

Why do people let this happen? You may think it's an issue of competence. After all, rational thinking is a skill to be developed, as I was reminded the other day. But one need not pass the bar to think and judge – remember, these are metaphors – and everyone has to make choices. Morals and judgment help them with that.

So there must be a different reason people refuse that help. As Rand points out, to judge is an "enormous responsibility", and many people are afraid of it. Since it is neither the defense's nor the prosecution's job to judge, I suspect that acting not as a judge but as a (metaphorical) lawyer or prosecutor allows people to evade that responsibility.

Some people would prefer to leave the courtroom of their mind altogether, but it is in session as long as they are alive. Short of destroying their minds, being a lawyer for their ideas instead of a judge is a common way to evade the responsibility of pronouncing moral judgment.

A fallibilist's job, on the other hand, is twofold:

1. He must learn to follow a rational, objective procedure for evaluating, accepting, and abandoning ideas. Read about this procedure here. It was originated by philosopher Karl Popper, who considered it to be the most rational procedure.
2. He must look into his own mind to discover whether it has been corrupted, to determine retrospectively when he has abandoned rational standards and played favorites with ideas, and to correct these mistakes.

The rule of law as an instantiation of the principle that personal preference must not override proper procedure is one of the great achievements of the West. But this principle has yet to materialize in individuals. Considering one's mind a courtroom, however idealized, helps one respect and meet the responsibility of judging ideas appropriately.