[Protagoras]

Is it in your rational self interest to become a murderer and a thief?

In the absence of right and wrong it might be.

I would never kill anyone because of my morality, but if I had no morality, I might kill you for disagreeing with me if I felt like it and thought I would suffer no ill consequences to myself.

But even though you try to personalize it, the truth is, you know that there are millions and millions of people who do that very thing all the time. The history of the world is nothing but the story of people killing each other and taking each other's stuff.

[Durus]

There is never an absence of right and wrong, only a absence knowing one from the other and even that isn't typical.

To answer my own question of you, it is not in your rational self interest to become a thief and a murderer as there are likely negative consequences to those actions. In fact the consequences so far outweigh the gains of said actions that it is not even close to being in your rational self interest. If you were to avoid the most obvious consequences your actions still would have added to a atmosphere of general lawlessness making you more likely to be the victim of the same crime.

[Junior]

I would never kill anyone because of my morality, but if I had no morality, I might kill you for disagreeing with me if I felt like it and thought I would suffer no ill consequences to myself.

But you will suffer consequences. Your victim's family might come after you or your family. Your society might decide that you're too dangerous to keep around (you might kill one of them next).

[b_sharp]

"But even though you try to personalize it, the truth is, you know that there are millions and millions of people who do that very thing all the time. The history of the world is nothing but the story of people killing each other and taking each other's stuff."

Sounds like a rather large trial and error experiment doesn't it?