The persistent urge of criminal law — my own field — is to find blame and guarantee retribution. If a blameworthy someone cannot be found, worry not; criminal law will invent her, or it.
In 1386, in medieval France, the tribunal of Falaise « sentenced a sow to be mangled and maimed in the head and forelegs, and then to be hanged, for having torn the face and arms of a child and thus caused its death ». Animals that commit crimes would have their day in court. If found guilty, the punishment was execution or — I guess for the ones that could afford a good lawyer — an order to leave town immediately.
Smaller animals, like pests or insects, were not off the hook either. The lesser crimes of infestation or destruction of crops would result in excommunication from the church. Barthelemy Chassenée, a leading French jurist of the sixteenth century, wrote a whole Treatise on the Excommunication of Insects. As late as 1916, an elephant named Mary was hanged in Tennessee for murdering her own trainer. Over 2500 people gathered to witness the execution of « Murderous Mary ».
Criminal law has been rationalized since then. The core moral thread that holds the modern criminal law doctrine together is that only morally culpable humans should be convicted of a stigmatic criminal offense. A pig cannot be a sensible target of blame. Neither can a child, nor a mentally ill person, nor an offender who lacked the necessary « guilty mind » (that is, she did not act with intention, recklessness or criminal negligence), nor an offender who acted in self-defense or in a state of necessity. The culpability principle that stands as the moral foundation of twentieth-century criminal law doctrine is a victory of rationality. The loser, here, is the human id that cannot let go — that asks: « Am I supposed to forgo blame because the conduct of the perpetrator of the crime did not match the legal test of recklessness? »
A similar, but newer challenge for that same id: am I supposed to forgo blame because the perpetrator of the crime was a robot?
E.P. Evans, The Criminal Prosecution and Capital Punishment of Animals (London: W. Heinemann, 1906), pg. 140.
William Ewald, « Comparative Jurisprudence(I): What Was it Like to Try a Rat », University of Pennsylvania Law Review 143, p. 1900.
Incident Number 4, in Sean McGregor, ed., Artificial Intelligence Incident Database.
Incident Number 24, in Sean McGregor, ed., Artificial Intelligence Incident Database.
Incident Number 28, in Sean McGregor, ed., Artificial Intelligence Incident Database.
See, for example, S.J. Morse, « Psychopathy and criminal responsibility », Neuroethics 1 (2008), claiming that someone who is not capable of moral understanding (not responsive to moral reasons), like a partial psychopath, should not be criminally responsible, and P. Litton, « Criminal responsibility and psychopathy: Do psychopaths have a right to excuse? » Handbook on psychopathy and law (2013), which claims the opposite, i.e., that instrumental rationality even without responsiveness to moral reasons is enough for criminal responsibility.
The plea of Clarence Darrow, August 22nd, 23rd & 25th, MCMXXIII, in defense of Richard Loeb and Nathan Leopold, Jr. (Chicago : Ralph Fletcher Seymour, 1924).