The received picture of rationality, nowadays in trouble, is contrasted with the "argumentative" conception, inspired by Paul Grice's proposal to define rationality as an agent's desire that his or her moves are supported by reasons and a capacity to satisfy that desire at least to some extent. Some implications of the argumentative conception of rationality are unfolded: it involves a first-person perspective, requires criteria for the attribution of the capacity to justify one's moves, and allows for failures to behave or think rationally. Attribution of argumentative rationality to a human being does not follow from final evidence, but (when conceived as the attribution of an essential, as opposed to contingent, property), coincides with the acknowledgement of personhood, which in turn, being at least to some extent a matter of choice, is revealed to be an ethical task. So the argumentative conception of rationality may help us see why it still make sense to think of man as a rational being.
