Everything happens at the margin. Those penalties undoubtedly push the margin towards less murder. If you don't think it is a disincentive, then what is the point of jailtime, etc.? You want to reduce utility by making someone suffer for no reason (and at the same time place living cost burdens for the prisoner [or in the case of the death penalty even more fees in state attorneys] on the taxpayer)? That seems cruel and unproductive. I see the purpose of jailtime as an aggregate utility boon because of the incentive effect. But we probably disagree there.
Where there is no room for disagreement though is that people respond to incentives. If government is setting policy anyway, they should always consider the incentives or you will get more unintended consequences.
Since you brought the discussion to specifics, I would rather pay more and enact the death penalty on those who have taken the life of another human, than support them LIVING in a prison. That might serve as a deterent for some, but definitely not for all.
Most who would commit murder rarely stop and think of the penalties.
Oh, I'm not going to stab you because I might end up in jail is not usually heard at the scene of a crime.
Back to the actual discussion at hand, tax related incentives.
Being that I'm not such a rare and unusual creature in that I don't itemize, what could be, in your opinion, the reason that people such as me give their time, labor and money to charitable causes?
