Getting guilt right and what punishment to dispense to the guilty are different questions. For example you could have 100-member juries with unanimous verdicts required, but also execute anyone convicted of any crime.

> Getting guilt right and what punishment to dispense to the guilty are different questions.

I disagree.

If your legal system executes people, they are inseparable questions.

I would generalize to say that the more severe your sentences, the more those two questions are related.

It sounds like you two are disagreeing over the unmentioned error rate.

If I get a parking ticket unjustly, it may piss me off, but it isn't a big deal. If I am convicted of a serious crime unjustly, it matters far more.

Whereas the grandparent, I think, is asserting the guilt or innocence is (or should be) an objective fact independent of what anyone does about it.

I think you're arguing a different point. Sure there's a relationship, but these are not the same question:

"Did Joe kill Dave?"

"Given that we've decided that Joe did kill Dave, what should Joe's punishment be?"

They can become one.

For instance:

  1) Did Joe steal that apple?
  2a)Do we chop off Joe's hand, like law says? 
  2b)Do we make Joe repay the apple, and get community work?

There are people (myself included) that would answer the 1 question differently depending on the second question