The mediation of the practico-inert which grounds the social materialism of the Critique would be nothing if it were not situated in relation to Sartre’s unique conception of need. In a word, need motors the dialectic of action and matter within praxis; philosophically, it is that through which materiality is ontologically basic to matter. Early in the Critique, Sartre outlines the broad contours of his understanding of need:
Everything is to be explained through need [le besoin]; need is the first totalising relation between the material being, man, and the material ensemble of which he is part. This relation is univocal, and of interiority. Indeed, it is through need that the first negation of the negation and the first totalisation appear in matter. Need is a negation of the negation insofar as it expresses itself as a lack within the organism; and need is a positivity insofar as the organic totality tends to preserve itself as such through it…; the negation of this negation is achieved through the transcendence of the organic towards the inorganic: need is a link of univocal immanence with surrounding materiality insofar as the organism tries to sustain itselfwith it…; as soon as need appears, surrounding matter is endowed with a passive unity, in that a developing totalisation is reflected in it as a totality: matter revealed as passive totality by an organic being seeking its being in it – this is Nature in its initial form.<sup>184</sup>
Following Marx and Engels, Sartre’s conception of need proceeds from the physiological and biological reproduction of human life. The living body is absolutely crucial to the Critique: it is an originary condition of totalisation and the first coexistence of praxis and matter – of ground and product – in time and space. The body is thus an organic totality that ‘acts on inert bodies through the medium of the inert body which it is and which it makes itself.’<sup>185</sup> However, in sharp contrast with Marx, it is not surplus but scarcity [la rareté] which for Sartre underlies this metabolism between humanity and nature. Scarcity, not surplus, fuels history, such that, in Marx’s terms, new needs are created and productive forces expand because there is scarcity.
<sup>183</sup> See Lucien Goldmann, Marxisme et sciences humaines (Paris: Gallimard, 1970), 330-31, as well as Flynn’s response to Goldmann in Sartre and Marxist Existentialism, 173-77.
<sup>184</sup> Sartre, CDR 1, 80-1. This conception of need safeguards dialectical reason from being killed twice over ‘to make sure it is dead – the first time by claiming to have discovered it in Nature, and the second time by suppressing it within society.’ Ibid. 712.
<sup>185</sup> Ibid. 82. ‘…the matter outside it subjects the living body to an inorganic statute precisely to the extent that it is itself transformed into a totality.’ Ibid. 81.
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