When we think about what others believe and want, we are usually affected by what we know about their attitudes. If I’m aware that another person believes something, I have an opportunity to agree or disagree with it. If I think that another person wants something, I can endorse or disapprove of her desire. The importance of such reactions to attributed beliefs and desires has thus far been overlooked in philosophy of mind where the focus has been on explanatory and (...) predictive roles of attitude attribution. The primary goal of this thesis is to fill this lacuna and to articulate the indispensability of such reactions – agreement/disagreement and endorsement/disapproval – for social cognition. In the process of doing it I also show how these initial reactions ground certain further possible responses in intersubjective communication: manipulation, negotiation or adoption of attributed attitudes. The second aim of this thesis is to explicate what is it about belief and desire attributions that makes the responses I’ve described possible. Because one can agree or disagree both with beliefs and assertions and endorse or disapprove both desires and requests, I argue that we should understand belief attributions in terms of assertions and desire attributions in terms of requests. When we think what someone believes and wants, we treat her as a conversation partner because her attitudes call for the same responses as speech acts do, even if she hasn’t made any explicit assertion or request herself. In short, beliefs and desires have communicative significance. Given such significance, we can also see what one needs to take into consideration when attributing these attitudes to another. My answer in the thesis is that belief and desire attributions have to be grounded in facts about the behaviour and well-being of attributees and that these facts also constitute the nature of beliefs and desires. (shrink)