Around here, we seem to have a tacit theory of ethics. If you make a statement consistent with it, you will not be questioned.

The theory is that though we tend to think that we're selfless beings, we're actually not, and the sole reason we act selfless at all is to make other people think we really are selfless, and the reason we think we're selfless is because thinking we're selfless makes it easier to convince others that we're selfless.

The thing is, I haven't seen much justification of this theory. I might have seen some here, some there, but I don't recall any one big attempt at justifying this theory once and for all. Where is that justification?