Rawls' "Original Position" and Its Dilemma

Original position is the logical starting point of Rawls' justice theory,it is not being set to exist in history,but just thinking of existence,namely,the existence of a hypothetical state. Rawls makes political philosophy return to contract theory through this assumption,implementing the revival of the contract theory in the western history of moral philosophy,but the theory has many difficulties,which embody in the environment of justice,the design of the veil of ignorance and the object of selection,etc.