Sidgwick - Overall Structure

The principles of justice are those chosen in the original position. We could call them the 'correct' principles if we want, although Rawls doesn't use that word.
The principles chosen are to be accepted and followed because they are the outcome of a fair procedure. There is no independent criterion for choosing principles.
The original position is a fair procedure for choosing principles because (a) it embodies weak but widely accepted moral notions about justice found in our society, and (b) it includes a veil of ignorance that prevents bias and self-interest from influencing the choice of principles.
We know that the original position embodies widely accepted notions found in our society because the principles chosen in the original position are in a reflective equilibrium with our most considered judgments about justice as it applies to specific cases.

I think we're ready now to open the discussion and criticize Rawls' theory. That's what we'll do at our next session.