The public rationale for the death penalty is (necessarily) based on an implicit error of “folk logic”; this error underlies its ethically coarsening consequences.
My discussion is grounded in a few basic observations about the criminal-punishment system, which is three-tiered: fines, incarceration, and death. Each tier is supposed to correspond to a qualitative worsening of offense: malum prohibitum, malum in se, and heinous crime (minimally involving murder). The rationale, in short, is that taking a life is the ultimate crime, deserving loss of life, the ultimate punishment. Although we can question whether loss of life is really the worst that can happen to someone, that’s the way it’s presented, and it perhaps necessarily appears so to the mass mind.
But, accepting the premise, the rationale pretends a nonexistent symmetry, the asymmetry being in the capability of one person to inflict harm on others in great number. If death is the ultimate punishment, it doesn’t follow that taking life is the ultimate crime: a criminal is but a single person capable of harming many.
The 19th-century philosopher Georg Hegel diagnosed the cognitive bias of failing to see that change in degree (“quantitative” change), carried far enough, produces a change in kind (“qualitative” change). In this light, look at the banking collapse that led to the U.S. mortgage crisis, involving crimes by bankers that have yet gone unpunished and which would never be punished by execution. (If you need worse, consider the industrialists who funded Hitler’s ascent.) Ordinary “thin utilitarian” public-moral intuition tells us that knowingly causing suffering for millions is worse than even the sadistic murder of a single person; if there were a qualitative category of heinous crimes, at some tipping point sublethal mass crimes would become heinous. You might advise don’t stop executing murderers, rather expand execution to heretofore unpunished crimes of massive scale, but we find no point of qualitative inflection.
From this artificial abstraction of the act of individual murder stems the fundamental misdirection society incurs when it institutes a death penalty, which reinforces and accentuates the near-mode bias that carves, with the knife of extraordinary public vengeance, horrific individual acts out of their societal context. The social symbolism in capital punishment dwarfs (at most historical junctures) any specific deterrence effect. Capital punishment engineers a public mentality myopically preoccupied with vengeance against victims of far worse wrongs consequently ignored.
This analysis rests on the insight that public consciousness imputes a qualitative distinction between deeds where the law applies qualitatively different punishments, and it is confirmed by the fate of another potential tier of punishment. The deliberate infliction of pain is proscribed: we don’t flog criminals; but isn’t it curious that we regard killing as humane and flogging not—when we might execute for killing, but never for nonlethal flogging? Why the reversal of values when assessing crimes and their punishment? My explanation is that flogging competes with long-term incarceration, and they can’t easily co-exist, since we would then distinguish punishments without reciprocally distinguishing crimes.
When flogging and stoning reappear, they serve a corresponding false distinction in crimes, and crimes can be special by being no crime at all; theocracies have resurrected flogging and stoning to punish thought crimes. Legally manufacturing a spurious moral hierarchy—such as one including capital crimes—foments mass myopia.