Ask people why they support the death penalty or prolonged incarceration for serious crimes, and the reasons they give will usually involve retribution. There may be passing mention of deterrence or rehabilitation, but the surrounding rhetoric gives the game away. People want to kill a criminal as payback for the horrible things he did. Or they want to give "satisfaction' to the victims of the crime or their relatives. An especially warped and disgusting application of the flawed concept of retribution is Christian crucifixion as "atonement' for "sin'.
Retribution as a moral principle is incompatible with a scientific view of human behaviour. As scientists, we believe that human brains, though they may not work in the same way as man-made computers, are as surely governed by the laws of physics. When a computer malfunctions, we do not punish it. We track down the problem and fix it, usually by replacing a damaged component, either in hardware or software.
Basil Fawlty, British television's hotelier from hell created by the immortal John Cleese, was at the end of his tether when his car broke down and wouldn't start. He gave it fair warning, counted to three, gave it one more chance, and then acted. "Right! I warned you. You've had this coming to you!" He got out of the car, seized a tree branch and set about thrashing the car within an inch of its life. Of course we laugh at his irrationality. Instead of beating the car, we would investigate the problem. Is the carburettor flooded? Are the sparking plugs or distributor points damp? Has it simply run out of gas? Why do we not react in the same way to a defective man: a murderer, say, or a rapist? Why don't we laugh at a judge who punishes a criminal, just as heartily as we laugh at Basil Fawlty? Or at King Xerxes who, in 480 BC, sentenced the rough sea to 300 lashes for wrecking his bridge of ships? Isn't the murderer or the rapist just a machine with a defective component? Or a defective upbringing? Defective education? Defective genes?
Concepts like blame and responsibility are bandied about freely where human wrongdoers are concerned. When a child robs an old lady, should we blame the child himself or his parents? Or his school? Negligent social workers? In a court of law, feeble-mindedness is an accepted defence, as is insanity. Diminished responsibility is argued by the defence lawyer, who may also try to absolve his client of blame by pointing to his unhappy childhood, abuse by his father, or even unpropitious genes (not, so far as I am aware, unpropitious planetary conjunctions, though it wouldn't surprise me).
But doesn't a truly scientific, mechanistic view of the nervous system make nonsense of the very idea of responsibility, whether diminished or not? Any crime, however heinous, is in principle to be blamed on antecedent conditions acting through the accused's physiology, heredity and environment. Don't judicial hearings to decide questions of blame or diminished responsibility make as little sense for a faulty man as for a Fawlty car?
Why is it that we humans find it almost impossible to accept such conclusions? Why do we vent such visceral hatred on child murderers, or on thuggish vandals, when we should simply regard them as faulty units that need fixing or replacing? Presumably because mental constructs like blame and responsibility, indeed evil and good, are built into our brains by millennia of Darwinian evolution. Assigning blame and responsibility is an aspect of the useful fiction of intentional agents that we construct in our brains as a means of short-cutting a truer analysis of what is going on in the world in which we have to live. My dangerous idea is that we shall eventually grow out of all this and even learn to laugh at it, just as we laugh at Basil Fawlty when he beats his car. But I fear it is unlikely that I shall ever reach that level of enlightenment.