Judge Posner talks about the uncertainty of American law and why this means that Judges can’t always makes cost-benefit analysis. He goes on to talk about his ideological development and reacting negatively to the Vietnam protests.

Question: Does personal experience shape your approach to the law?

Richard Posner: Well I think very substantially. This is the fun of it actually. American law is extremely uncertain. And now the majority, even, given that the majority of cases are cut and dried if you look across the whole American system with their millions of cases filed every year. And most of them have no merit, or some have obvious merit. But when you’re talking about a federal appeals court, a significant fraction of the cases that come to us arise in unsettled areas, or the facts are very uncertain. When you get to the Supreme Court, the percentage of really indeterminate cases are really much higher. But at our level it’s high. It is significant.

There are two kinds of uncertainties. Statisticians make a distinction between risk and uncertainty. Risk is where there’s uncertainty, there’s a lack of certainty, but some probability can be assigned to the risk. So you can deal with it. Uncertainty in the way some statisticians use the term means there’s no probability that can be assigned to this risk, but you still have to deal with it.

So an example would be suppose you’re deciding whether to get married. You can actually assign a risk of divorce. You can look at the statistics on divorce and say, you know, 50 percent of marriages end in divorce. But you don’t know the probability of your marriage ending in divorce, right? So that’s uncertain. You still have to make a choice, but you couldn’t assign a probability. You couldn’t do a cost-benefit analysis. Well that’s the position we’re in much of the time, and those are the interesting cases. And if you think of the marriage choice, what is going to determine your decision is going to be highly personal to you. And that’s true with the judges.

So your ideology, your temperament, your response, your experience. You may have been a defense lawyer – a criminal defense lawyer. That’s giving you some perspective. If you’ve been a prosecutor, that’s giving you another perspective. Academic, something else. If you have what’s called an “authoritarian” personality, you’re going to be conservative, and you’re probably going to be very rule oriented. You’re going to set a very high value of “definiteness”. And if you’re the opposite personality, not. And as I mentioned Justice Breyer, he doesn’t like rules. He likes very general standards. And some of his colleagues are the opposite, like Justice Scalia. He really likes rules. He doesn’t like standards. And that, I think, is the temperamental difference. Temperament being shaped by biological factors, but also by upbringing, experience, the times in which you grew up.

One of the things I know shaped my own ideological development is I reacted very negatively to the riots and protests in the Vietnam period. I really dislike that stuff. And I think that had an effect.

Now of course other people reacted the opposite. They thought this was terrific. You know they’re nostalgic for it.

So the same experiences can have different effects on people depending on I think, you know, deep psychological factors which are _________ biological.

But as a I say, whenever you have people who are making decisions that are not . . . cannot be made in a kind of an algorithmic way in applying a formula.

And to an economist, the epitome of algorithmic decision making is cost benefit analysis. And it would be nice if in a case we could say that we decide one way, there’s some probability of the following measurable adverse consequences in future cases as a result of adopting this rule. But you rarely can do it. In a larger number of cases, you can’t do a statistical analysis, but you know that the adverse consequences of one choice greatly outweigh that of the other. But then as I say, there’s a large number of cases where you simply do not know. And so your personal characteristics then shape your decision.

Recorded on: Nov 21, 2007