I'm sure you did. I'm also sure you've never murdered or raped anyone. We're not talking about you though, we're talking about those who have murdered or raped someone, and what they know or don't know. Remember, just because you understand something doesn't mean everyone does or that everyone can.
Yes, but the average person understands 'murder is wrong'. It's a pretty basic concept. That doesn't mean they're incapable of doing it. Normal people murder others all the time, and they KNOW what they did was wrong.
Imagine this, though. There's this guy who's moved to Sweden from the States. One day a robber breaks into his house and starts threatening his wife with a gun. The robber hasn't noticed the guy, who manages to sneak up on him from behind and shoots the robber. The robber dies.
Acording to Swedish law that's murder (sneaking up on someone from behind and shooting him is too cold blooded for a manslaughter label). Does that mean the guy thinks murder is right? I'm sure he'd say "no, but that wasn't murder, it was self defence". IE the guy thought what he did was justified (and justified actions aren't wrong). That's usually the case when someone does something wrong - they come up with a reason why it wasn't wrong in their case. Sometimes in hindsight, but in those cases it's still quite clear that there wasn't any "I shouldn't do this" knowledge stopping them from doing it. Or it was undercut with them not seeing any alternative solutions (IE they thought their options was even more wrong).
So what about a mafia hitman or an assassin? Are you saying they just don't "know" what they are doing is wrong or illegal? I think most of them just don't CARE. I've done morally wrong things in the past - not rising to the level of murder, obviously - and committed these acts knowing full well they are morally wrong,
but I did them because I knew I would benefit or someone I disliked would suffer. I don't buy the Platonic idea that "they just don't know its wrong!" These are pretty basic concepts, and sure, you can come up with gray area examples (your 'castle doctrine' one is pretty good), but people know that murdering some dude because he slept with your wife or because you want his money is morally wrong.
All in all, pepole who commit crimes tend to think they have solid reasons for doing so (or no solid reasons not to). At the time of the crime, anyway.
No disagreements here, but I think those solid reasons for doing it speak for their gain/etc and doesn't mean they weren't aware of what they were doing is wrong. For instance: when I was a kid, I knew taking money out of my mom's purse so I could go buy a video game was wrong. Did I do it anyways? Yep, because I wanted that game.
(By the way, be aware that I'm not at all sure this is actually what Swedish law would say, so don't take my word for it this is how it works. I'm fairly certain it would at least be "causing someone elses death", but it might also be manslaughter or even murder. I chose murder because that's what would give my example the most power. I'm also not sure whether you'd get away with "self defence" here or not.)
No, it's a good example, and its one that'd be valid in some U.S. states. For example: California has pretty open "Castle Doctrine" laws - so if someone breaks into your house/business and you are "afraid for your life", it's legal to shoot and kill them. In fact, it's actually legally better for you TO kill the person, since if they're alive they can contest your claim and potentially sue you or land you in jail.
In my current state of Virginia, I *believe* there is no Castle Doctrine, so I have no inherent right to shoot and kill someone breaking on my property. In other states, you have a modified Castle Doctrine where you can only shoot them if flight is impossible, etc.
Now, the point of this is, there are always areas where "the law" is fuzzy and where there IS moral debate over whether or not something is wrong or not. I, for one, have no moral or ethical issue with the targeted killing of Anwar al-Awlaki. Others consider it murder of a US Citizen. However, on a very basic level, we understand "murder is wrong" or "rape is wrong" - yet people still do it.
That's right, and I don't blame criminals (when I can help it - nobody's perfect). That doesn't mean I don't think "punishing" them is a good idea. It's just that when I put murderers in prison I do so because they are a danger to society and needs to be isolated, not because they deserve to suffer for what they've done.
Übereil
I do it for both reasons, but I'm a pretty cold and uncaring bastard. If there was a pill or a surgery or treatment that would make them safe and unable to commit the crime again, I'd release them after a decade or two for murder.
EDIT:
I'll also say, though, that if we ever DID live in a society where people *Weren't* punished for their actions (say if Dartagnan's 'justice for the victims is stupid' idea spread) and someone murdered my hypothetical friend/loved one, I'd go and kill them myself - and why shouldn't I? If society fails to secure justice for victims, they'll secure it for themselves.