Yes, Criminals of violent crimes are usually not rational
calculators
We also have studies that suggest that most criminals either did
not think they would get caught (rightly so, since the vast
majority of crimes remain undetected), or deliberately blocked out
all thoughts of the consequences of their actions.
Yet, i remain unconvinced that individual deterrence completely
doesn't work. The thing about all these research is that they do
not know about those who *have* been deterred. These criminals are
criminals because they have committed the crime and have been
caught.
Re Innocent deaths, I agree. That imo is the strongest argument
agaisnt the death penalty. We must recognize that the Criminal
Justice System does not always get things right, and there is no
going back from murdering someone. Morally speaking, i would rather
we just keep them in jail for the rest of their lives.