 Of course, if one were to adopt the extensional point of view, and hence identify equivalent propositions, the contradiction above could not be derived. Russell, however, sticks to an intensional point of view, stressing that equivalent propositions often can be quite different. So one is apparently forced to reject the assumption that propositions form one type, and hence to require that they ought to have various types, while logical products ought to have propositions of only one type as factors.