On segment of the show is about a man whose self control is impacted due to some mental disorder. The question is: Should he be treated more leniently because it's not his fault, but his brain's? The conclusion, that I have to agree with is: Of course not! You ARE your brain.

1. Retribution - nope; predisposition to crime doesn't change the appropriate retribution for the act;

2. Deterrence - nope; if we believe in deterrence then we definitely do not want people predisposed to crime to feel that they might get off lightly because of that; those people would be the prime "focus group" of deterrence that'd be threatened to keep their violent tendencies in check or suffer harsh consequences.

3. Rehabilitation - it depends; are the brain factors making you prone to violent behavior curable ? It might change the nature of appropriate punishment from imprisonment towards forcible curing = brain modification; but it's not really a mitigating factor there, more like an agravating one that requires more/different rehabilitation.

4. Incapacitation - it's an aggravating factor in that case; if you're genetically predisposed to violent crime, then according to incapacitation doctrine you should be isolated from society more/longer than someone who is less likely to reoffend.

5. Reparation - nope; no effect.

6. Denunciation - okay, for this theory it would be a mitigating factor. However, denunciation is generally applied to nonviolent crimes (ethics/morals issues); for murder generally we focus on combination deterrence, rehabilitation and incapacitation.

A cautionary tale about drawing conclusions from small sample sizes.