[rmeister0]

This is the “depravation of sale” argument I referred to above. I think its flawed at the logical level and also it is based on pre-digital assumptions about property and ownership. The problems lead to the absurdity of the claim that B has stolen from C.

The point here is that two copies of X have been sold, and C has only been paid for one.

If that isn't theft, then what exactly is it?

It only works in cases where B would have purchased X from C had she not copied it from A.

I hear this argument a lot, and I think it is looking at it the wrong way. If B was not willing to purchase X from C, than B should go without X. Period. The argument implies that it is morally acceptable to take something that you would not be willing to pay for. If I walk out of the Best Buy with a CD under my arm, telling the judge "it isn't theft because I wasn't going to pay for it anyway" wouldn't hold water. There are still two copies existing where C has only been paid for one. Either I pay for the luxury of owning X, or I don't pay and I don't get to have the luxury of owning X.

It might be helpful to think about these things the other way round. Imagine I have a magic bag, you put in one apple and two come out. I go to a fruit shop, buy an apple and duplicate it with my magic bag. I give you the apple. According to your logic that would make you a thief? That’s absurd isn’t it?

This analogy is highly flawed. The magic bag creates the apples by itself without any labor or raw materials required. Real life does not work that way; the items being duplicated still have to originate somewhere, somehow, with real labor done by real people. Music doesn't compose, perform, and record itself. Movies don't write, direct, act, edit, and post themselves. Books don't write themselves (unless you have Stephen King's PowerBook).

But again, if it isn't theft, than what is it?