that all validity claims are either already vindicated or could be vindicated. Examining the validity of speech Habermas claims that communication rests upon a non-egoistic understanding of the world, which is an idea he borrowed from thinkers like Jean Piaget. A subject capable of a de-centered understanding can take up three fundamentally different attitudes to the world. Habermas refers to such attitudes as dimensions of validity. Specifically, this means individuals can recognize different standards for validity—i.e., that the validation of an empirical truth claim requires different methods and procedures than the validation of subjective truthfulness, and that both of those require different methods and procedures of validation than claims to normative rightness. These dimensions of validity can be summarized as claims to truth (IT), truthfulness (I), and rightness (WE). So the ability to differentiate between the attitudes (and their respective "worlds") mentioned above should be understood as an ability to distinguish between types of validity claims. M. Cooke provided the only book length treatment of Habermas's communication theory. Cooke explains: "when we adopt an objectifying attitude we relate, in the first instance to the objective world of facts and existing states of affairs [IT]; when we adopt a norm-conformative attitude we relate, in the first instance, to the social world of normatively regulated interactions [WE]; when we adopt an expressive attitude we relate, in the first instance to the subjective world of inner experience [I]". (Cooke 1994) This is fundamental to Habermas's analysis of communication. He maintains that the performance of any speech act necessarily makes reference to these dimensions of validity, by raising at least three validity claims. One way to grasp this idea is to take an inventory of the ways in which an attempt at communication can misfire, the ways a speech act can fail. A hearer may reject the offering of a speech act on the grounds that it is invalid because it: presupposes or explicates states of affairs which are not the case (IT); does not conform to accepted normative expectations (WE); raises doubts about the intentions or sincerity of the speaker (I). Of course, from this it follows that a hearer who accepts the offering of a speech act does so on the grounds that it is valid because it: presupposes or explicates states of affairs that are true (IT); conforms to accepted normative expectations (WE); raises no doubts concerning the intentions or sincerity