[Someone]

Ethically? I bet they will kill them thousands of times during development.

Suppose you, at one stage, have a simulation of a brain that isn't quite there; it talks and sees, but it's audio system doesn't work right. What do you do?

Even live debugging to repair it can be controversial (http://en.wikipedia.org/wiki/Cochlear_implant#Criticism_and_...)

[fragsworth]

I don't see anything unethical about shutting it off. If nobody is emotionally attached to it, and it doesn't suffer when it is shut off, who is harmed by the shutdown?

[Someone]

Consider a person without relatives or friends. Would you consider it ethical to shut him/her off, as long as that person didn't suffer from it?

[fragsworth]

As long as they do not care that they could be "shut off", I see nothing wrong with it. If they dislike that notion (like real humans do), then the possibility of shutdown would cause suffering and would be immoral/unethical to allow.

You're assuming that the machines will care about being shut off - we would probably design them so that they don't care about this, because this makes them easier to work with. And then it's no longer unethical.