Our concern with the issues raised by analytical philosophy should not allow us to forget the challenge represented by contemporary forms of scepticism concerning the status of science in general. One strand of post-modern philosophy in particular prides itself on deconstructing the kind of "grand narratives' that once sustained the project of all-encompassing knowledge. According to Jean-François Lyotard (1979/83), notions like those of the emancipation of humanity, of a universal teleology of spirit, of a universal hermeneutics of meaning, all expressed the same kind of desire for a single ultimate truth that should henceforth be relinquished in favour of an emphatic recognition of plurality. It is of course clear that deconstruction of this kind is not particularly new since its origins can be traced to the later Heidegger, and before that to Nietzsche, and earlier still back to Kant himself, whose "Dialectic" reflects a similar atmosphere of critical thought. And far from recognising or regretting the collapse of the traditional legitimating framework of thought, namely that of 'special metaphysics' as a whole, in a pessimistic or melancholy spirit, Kant welcomes it as a kind of liberation. In this sense we may say that one grand narrative at least, that of emancipation, is justified after all.