On the internet, nobody knows you’re a dog. . .

. . . or a maladjusted government-loving fear-slave. Or simply a lousy lawyer.

The internet is mostly terrible that way. Anonymous people say things that they would never say for attribution; even using their names, people make claims about themselves among strangers that would be risible to those who know them. (Anyone with a law degree can, for example, hold himself out to be a DUI lawyer, regardless of his lack of any actual experience in the field.)

The anonymity made possible by the internet is valuable in certain narrow circumstances. For example, the Publius Exception, which applies when the writer is dealing with matters of pure thought (rather than fact or opinion), so that the writing’s effect does not depend on its writer’s credibility; and the Candidus Exception, which applies when, by writing important truths, the writer places himself in danger that might prevent his writing further.

The Candidus Exception is far too often invoked to justify throwing anonymous mud. It can justify anonymous commentary and attacks on those in power, but not craven attacks on other ordinary people. Those who would engage in anonymous personal attacks online are the car-keyers of the internet. Keying the tsar’s car may be the act of a revolutionary, but keying my car is the act of a coward. If you’re writing anonymously under the Candidus Exception, don’t throw away your credibility with attacks against your fellow citizens.

The Candidus Exception also doesn’t justify publishing junk or untruth anonymously. If you’re writing anonymously under the Candidus Exception, say something important and true. Again, don’t squander your credibility with lies or irrelevancies.

When someone writes something on the internet and puts her name to it, everyone else has an opportunity to investigate the credibility of the writing. They can google her, or ask other people in the relevant community about the writer’s veracity, or even call up the writer to discuss.

When someone writes something anonymously, though, the last two options are unavailable. A reader can’t do any research in the real world to find out if the writer is someone who should be believed and followed. But the anonymous writer is a mysterious masked figure, and people in masks cannot be trusted.

How does the reader know whether to trust what that masked figure has to say? Plausibility and verisimilitude, for a start — if the unknown writer’s comment is improbable or seems untrue, it probably is.

If the anonymous writer has used the same mask before, that nom de web might be googlable, and a search might provide some insight into whether the writer has provided reliable information — has made predictions that have been proven true, for example — in the past.

If there’s a real email address attached to the comment, that too is googlable; it also provides a virtual way to contact the writer to discuss the matter and further judge her credibility. (A false email address, by contrast, is an automatic credibility eliminator.)

Finally, the reader can see what other credible sources say about the masked figure. (This is the web equivalent of asking others in the relevant community in the real world.) Do non-anonymous bloggers link approvingly to the masked figure, or non-anonymous commenters refer to personal knowledge of her? If they do, then some of the non-anonymous people’s credibility can be imputed to the masked one.

(An aside: has anyone created an online credibility index?)

One anonymous blogger who meets all these tests for credibility is Gideon of A Public Defender. Gideon is a Connecticut public defender who writes about all manner of legal and social issues (he is particularly concerned with gay marriage — not that there’s anything wrong with that). He is frequently cited by non-anonymous bloggers (like Scott Greenfield), he is reachable by email, and I vouch for him personally. If you don’t already read A Public Defender, I commend it to your attention.