I’m just about finished with this book, and I’ve found it very interesting. Laudan approaches the legal process  with strictly epistemological interests, asking whether it’s a good system if what we’re after is convicting bad guys and not convicting good guys. On the whole the answer is “no,” so he engages in some speculation about how we might make the process better at tracking the truth.

He knows, of course, that no system will be perfect. So one interesting question he raises is this: what degree of imperfection are we willing to tolerate? Clearly most of us would rather see some guilty people go free than see innocent people convicted — but how many? What’s the ratio? How many murderers or rapists are we willing to see go unpunished for every innocent person wrongly convicted? Let n represent this number. Previous legal theorists have suggested that n equals 5, 10, 100, and 1,000. Laudan seems to settle on 10, though probably just for the sake of making ensuing discussions a bit clearer and more definite. (I suppose experimental philosophy could try to settle this question.)

Laudan also explores what anyone could possibly mean by “beyond a reasonable doubt.” This is an important matter, as judges have to say something to jurors about what this means, and if they get it wrong, a case can be overturned. So what does it mean? Laudan claims that it’s usually understood subjectively: it’s when you feel very, very strongly that that defendant is guilty. But he rightly notes that this is not the sort of standard we’d accept anywhere else. Do we tell our scientists to regard a theory as proven when they feel really very sure about it, or disproven when they don’t? Instead, Laudan writes,

The principal question is not whether the jurors, individually and collecively, are convinced by the prosecution. The issue is whether the evidence they have seen and heard should be convincing in terms of the level of support it offers to the prosecutor’s hypothesis that the defendant is guilty.

So it looks like jurors ought to have some schooling in philosophy of science. That’s the only objection I have to Laudan’s recommendation: if only a jury of my peers could be relied upon to make that assessment!

The second half of Laudan’s book argues that the rules of what evidence can be presented slant courts too steeply in favor of defendants. That is, defendants already begin with some sort of presumption that they are innocent (lengthy and intriguing discussion about what this could mean, too), and it’s up to the prosecution to prove beyond a reasonable doubt that the defendant is guilty. Laudan basically thinks this is enough of a presumption of innocence. But the rules of evidence preclude the prosecution from bringing in a lot of relevant evidence, relevant for finding the truth of the case, if there is any reasonable doubt (there it is again) about how the evidence has been obtained. Laudan thinks this grotesquely exaggerates the presumption of innocence and makes for far too many false acquittals (i.e., letting the guilty go free). Of course, he wouldn’t argue that the prosecution should be allowed to present anything, however gathered; his claim is only that the existent rules make it too hard to present evidence that really would help the courts to track truth better.

I’m certainly unlearned about all of this, but my first reaction is that I’m leery of relaxing rules of evidence, if only because I don’t see any reason to believe that the police and prosecutors have any interest in getting to the truth as opposed to getting a conviction. There’s no incentive for them to get to the truth. In that context, a defendant needs very strong protection indeed against a very capable and sometimes ruthless team working very hard to put him in jail. Hey, I just want a fair fight.

In any case, I’m finding this a very interesting read.