Number of words: 562

First it must be noted that what we are talking about is not whether the threat of punishment deters people from crime. The question, much more specific than that, is whether the threat of death is of significantly greater deterrent force than the threat of long imprisonment. How does this question now stand?

I think the answer has to be that, after all possible inquiry, including the probing of all possible methods of inquiry, we do not know, what the truth about this “deterrent” effect may be. We know that, on raw data, there has been somewhat more homicide in capital punishment states than in non-capital punishment states. But we cannot  draw any valid conclusions from this, for factors other than the punishment system may easily explain the difference. The general problem that blocks knowledge here is that no adequately controlled experiment or observation is possible or (so far as we can see) ever will be possible. We have to use uncontrolled data from socirty itself, outside any laboratory. When we do that, there are two basic modes of procedure. One can compare, say, homicide statistics in states that, respectively have or do not have capital punishment, over the same period of time, before and after the abolition or reinstitution of capital punishment.

The inescapable flaw, of course, that social conditions in any state are not constant through time, and that social conditions are not the same in any two states. If an effect were observed (and the observed effects, one way or another, are not large) then one could not at all tell wheather any of this effect is attributable to the presence or absence of capital punishment. A “scientific” – that is to say, a soundly based – conclusion is simply impossible, and no methodological path out of this tangle suggest itself. When I last sampled this enormous literature, I found two scholars were arguing over where the “burden of proof” lay – wheather, that is to say, the man who asserts that capital punishment deters has to prove this proposition  or lose out, or wheather the man who asserts that it does not deter has to prove this proposition or lose out. When you observe that an argument is in that posture, you can be very sure that neither side has a convincing case. Nobody is arguing about where the “burden of proof” lies with respect to the assertion that families of five with incomes under $4000 are on the whole less well nourished than those with incomes $20,000.

Nor does “common sense” help. In the first place, one of the soundest maxims “common sense” is that one is to look for and respect evidence, acknowledging as unsolved those problems which the best evidence leaves unsolved. “common sense,” moreover, has little to say about the state of mind of people meditating murder or rape; you or I might think the chance of death would “deter” us more than would the chance of imprisonment –  but neither or nor most of my readers have ever seriously meditated murder or rape, and infact we have crime as a means of suicide? (It often doesn’t work, but that is true of all kinds of suicide attempt.) The possibility cannot be dismissed that capital punishment may in this way stimulate homicide. We just don’t know.

Excerpted from “Capital Punishment” by Charles Black Jr..