Specific Deterrence and Justice
A common argument given for causing harm to another person is that it will prevent that person from doing some harm in the future. Specifically, this type of reason is given to justify capital punishment, on the basis that the person who has been executed cannot commit murder a second time. This is called “specific deterrence.”
However, is it right to cause a person harm in order to prevent him from causing some harm in the future.
Psychological Test
To examine this principle, let us assume that a psychologist creates a battery of tests that can be given to High School students to determine if they would commit a future crime. By tracking those who take this test as they go through life, the test proves to be a reliable, though by no means perfect, indicator of whether an individual will commit a future crime.
Furthermore, let us say that it happens to be the case that the chance of success with this test is slightly greater than the recidivism rate for a particular crime. If the recidivism rate for a crime is 15 percent, let us assume that this test is 20 percent accurate when it comes to predicting who will commit a first offense. This means that one out of five of those who fail the test will commit the crime in question in the future.
Now, let us apply the moral principle, “It is permissible to execute a person in order to prevent him from committing a future murder.”
If this is a valid moral principle, then we have more of a reason to execute all of those who fail this test in high school than we do those who have committed murder. We should be letting murderers escape execution under conditions where we would execute a high school student who fails the test. This is because the high school test is, in our example, a better predictor (if only slightly) of whether a person would murder than the recidivism test.
This means executing all of those who fail the test, including the half that will not commit a future crime. We cannot just pick out those who fail the test who will commit a future crime, because we do not know who they are until after they have committed the crime. By then, it is too late. A victim’s life has been destroyed by our refusing to act. So, we need to execute all of them, it would seem.
This is the way that the Argument from Specific Deterrence works when applied to capital punishment. There are those who will be executed who, in fact, would never kill again. Those who argue for capital punishment on these grounds realize that we cannot distinguish those who will kill again from those who will not. Therefore, they argue, all of them should all be killed. Those who would otherwise commit a future crime, and those who would not because we have no way of distinguishing one group from the other.
By analogy, all high-school students who fail this test should be executed. This includes those who will commit a future crime, and those who will not.
Justice requires treating like cases alike. Whenever we come up with an example in which like cases are not treated alike, we have come up with an example of injustice.
This example gives us two tests for determining if a person will commit a future crime; a high-school psychology test, and the “having already committed a crime of the same type” test — of which, I am assuming, the first is slightly more reliable. If we are willing to kill those who have committed a crime to prevent them from killing again, but we are not willing to kill those who failed this test to prevent them from killing for a first time, then we have a case of like cases being treated differently. Our actions are not just. They are, in fact, immoral.
The Prior Offense Argument
There is a difference between those high-school students who fail the psychology test, and those who have committed murder that some may argue is relevant here. Those who have committed murder have, of course, committed murder, and deserve to be punished for their past actions. In committing murder they have given up their rights — rights that the high-school students who have failed the psychology test still possess.
The problem with this answer is that it changes the argument. The person taking this route is like the person who says, “My horoscope says that the test plane will almost certainly crash.” When it is pointed out that horoscopes are notoriously poor predictors of airplane crashes they say, “These wind-tunnel tests suggest that the plane will almost certainly crash.”
The second argument does not support the first. There is nothing in the second argument that says that the first argument, the horoscope argument, is any good. It is still the case that the horoscope argument needs to be thrown out, even if the wind tunnel tests provide meaningful results that point to the same conclusion.
Accordingly, the specific deterrence argument — the argument that it is permissible to kill a person in order to prevent a future crime — still needs to be thrown out. Proof of this still rests in the fact that those who fail the psychology test are even more likely to kill a person in the future, and yet they are not to be executed.
The Retributive Justice Argument
In this case, the defender of capital punishment is changing his argument — asserting now that murderers deserve to be killed for what they have done (not what they will do).
However, the failure of the specific deterrence argument creates a problem for the retributive argument.
Murder is an unjust killing — or an unjustified killing. I have demonstrated through the psychology test analogy that killing for the sake of preventing a future crime counts as unjust killing. We are not treating those with similar probabilities of committing a future crime alike, and this is the essence of injustice. Therefore, killing for the sake of preventing a future crime counts as murder.
Now, the argument has been shifted to “Those who commit murder should be executed.” However, this now means that those who supported execution for the sake of preventing a future crime should be executed. By means of this argument we must execute — or, at least, we acquire a moral permission to execute a whole lot of people to meet this demand, if this is truly what morality demands of us.
Of course, we can avoid this problematic conclusion by denying the premise that got us here — that those who kill unjustly should be executed. However, this defeats the retributive justification for capital punishment.
Conclusion
Ultimately, I am not opposed to capital punishment in principle. It is one form of punishment among many and, for some people, not necessarily worse than life in prison.
However, I do believe that those who decide to kill another person have an obligation to justify their actions. Using arguments with problems such as these suggest that the killer has reason to pause and reconsider whether he kills justly or unjustly. Anybody who kills without a good reason for doing so kills unjustly — that is to say, he commits murder.
This is more of an argument against the evil of sloppy thinking and rationalization when it comes to killing somebody. It is tempting for those who want somebody else killed to drum up some excuse for getting what he wants. Everybody tries to cast their own actions, or acting to fulfill their own desires, in the best possible light. This tendency does not go away when it involves a desire that somebody else die.
When this happens, the person who advocates killing is really only killing because he or she wants to — because it gives him some sense of satisfaction or pleasure that the other person has been killed. The rest is just excuse-making and rationalization. However, if we decide to condone this type of activity — if we decide to accept sloppy thinking when it comes to considering reasons to kill another person — we might need to reconsider why we consider murder to be wrong at all.