Given the avarice of man, the hard reality is that the threat of bad consequences, including public retribution posed by the legal system, is vital to secure human rights to life and property against predation. If men were angels, as James Madison said, we'd have no need of government. The sad part about prisons is that the most effective crime reducer is the intact family. Their passions forge their fetters. Criminality is purposeful human behavior.
Burglars also choose their targets by considering both risks and rewards.
Only after World War II did scholars begin to statistically study the effects of deterrence. Today a large body of scholarly literature generally confirms the value of punishment in the prevention of crime. Perhaps the most widely cited is Isaac Erhlich's 1973 study of punishment and deterrence in the Journal of Political Economy. One provocative study involving prisoners and college students came down firmly on the side of certainty. When tested, both groups responded in virtually identical terms.