[chongli]

The GP is talking about a bartender refusing to allow drinks to be taken outside. I think it’s fair to say that if there was no threat of the bartender getting in trouble, the GP could have walked outside with the drink, no problem.

This argument can be extended to cover murder, theft, drug use and any other crimes you might think of by examining people’s value systems. I think we can all agree that murder is against most people’s values but you can’t say it’s universal. Some people are okay with murder in different circumstances but they may not necessarily be psychopaths who crave murder to the detriment of all else. It’s these people that I think may be deterred by the threat of punishment for murder.

Furthermore, to complicate matters a little bit, there is the principle of marginal deterrence. If the punishment for murder is much more severe than for burglary, for example, you can expect a burglar to think twice before deciding to murder the home owner during a break-in. If, on the other hand, you punish stealing with the same severe penalty as murder (say, death penalty for either crime) then you risk incentivizing the burglar to murder anyone who might be a witness to the burglary.

Ultimately, I think the soundness of the principle of punishment as a deterrent derives not from the assumption that everyone has the same values (we don’t) but from the differences in everyone’s values. This helps society produce an outcome that would not otherwise be achievable if we required 100% consensus on every individual value.