Reflection on our ordinary practices of attributing both meaning and understanding lend support to CRS (Horwich 1998: 48-9; Wittgenstein 1969: 102-3). One would typically say of a word in a foreign language that it has the same meaning as one in English if it has the same role. And if a word has no discernible use, one would be reluctant to attribute it meaning. Correlatively, if a person is able to use a word correctly, and respond to its employment appropriately, one would usually claim that she understands it. All of these observations suggest that the meaning of an expression is its role within a language.
Feyerabend uses this reasoning to try to shed light on one of Popper's arguments, which says that we are always able to change any statement, even those reference systems that guide our critical thinking. However, the two thinkers reach different conclusions, Popper assumes that it is always possible to make a criticism once the new criteria have been accepted, so the selection can be seen as the result of a rationality " a posteriori " to the selection. While, Feyerabend's position is that this solution is merely a verbal ornament whenever the standards are influenced by Popper's first world, the physical world, and they are not just developed in the third world. That is, the standards are influenced by the expectations of their originators, the stances they imply and the ways of interpreting the world they favour, but this is strictly analogous to the same process of the scientific revolution, that leads us to believe that the thesis of incommensurability can also be applied to standards, as is shown by the following asseveration:
Moral contractualism is the view that the rightness and wrongness of our conduct is somehow to be understood in terms of some kind of actual or counterfactual agreement. This must be distinguished from political contractualism, which adduces agreements in order to account for the justice or authority or legitimacy of political institutions or decisions. Versions of contractualism differ in terms of how they specify the agreements. The two main versions of contractualism are Hobbesian contractualism (sometimes called “contractarianism”), which is based on the idea of a self-interested bargain or contract between self-interested individuals for the sake of individual gain, and Kantian contractualism, which is based on the idea of a morally constrained agreement among individuals who regard themselves and one another as free and equal persons warranting moral respect. This article will say something about the historical sources of contractualism, but will focus primarily on recent discussions.