The understanding of 'concrete freedom' in terms of transcendence within immanence, whereby the diagrammatic subject is metonymically displaced beside it, has emphasised the irreducibility of freedom to any positive determination of human being. This chapter elaborates the fundamental 'negativity' of this ontology of freedom through its comparison with the influential account of the concepts of liberty offered by Isaiah Berlin. Berlin's affirmation of pluralism, which accords with Michel Foucault's claim for the 'indignity of speaking for others', finds its conceptual expression in the notion of 'negative liberty'. In contrast to a facile 'postmodernist' attitude, the attribution to Foucault of a certain metaphysical orientation has no derogatory connotations, but on the contrary dissociates his thought from a mere 'historicism'. Any philosophy that deserves to be taken seriously is necessarily metaphysical, even in its attempt to overcome metaphysics: a 'metaphysics of absence' that appears a fitting name for Foucault's ontology of freedom is by no means equivalent to an 'absence of metaphysics'.