I believe most European criminal law is divorced from the concept of retribution. Only deterrent, the &#x27;reeducation&#x27; of offenders and the active prevention of keeping a dangerous person locked up are valid reasons for incarceration.<p>On a practical level, I believe the idea is that longer sentences do not provide any additional deterrent. Nor do they provide better opportunities for reintegration. Both effects probably see decreasing marginal utility with longer sentences. Even more practical: most violent crimes are committed by males aged 18 to 30. 18 + 16 = 34.<p>On an ethical level, European law often relies on the concept of &#x27;dignity&#x27; which is ill-defined but (for this purpose) interpreted to mean that even hideous crimes do not justify the destruction of all of a person&#x27;s future.