The characteristic peculiarity and tension of Spinozism is most striking when one raises the question of change. Doubtless this question could not remain external to a thought that is defined above all as an ethics, and which, under this heading, is inseparable from an idea of progress (ad majorem perfectionem transire), elaborated on the basis of an incessant oscillation (in continua vivimus variatione), in relation to a fundamental permanence (immutabilitas Dei). Nevertheless, this schema, which after all is only a truism of moral philosophy, tells us nothing of Spinoza's originality. It must be completed, or rather troubled, by what we might call the paradoxical triangle of Spinozism: to progress is ultimately to learn to conserve oneself; and the work of conservation constantly runs up against the question of transformation. The key to this triangle, so to speak, is given at the end of the Ethics, when – notwithstanding his critique of ideas of chimeras and metamorphosis – Spinoza tosses out the great contradictory image of the infans adultus, the ‘adult child’, which refers back to a whole set of texts whose problematic connections it reveals.

The notion of transformation, in the seventeenth century, still belonged to the domain of mystery: it was of interest to the theologian and alchemist, and one could point out that the theology of mysteries itself required that of alchemy. We know what scorn Spinoza had for the fundamental belief of Christianity, that of the Incarnation, or of God become man. We also know the mechanistic approach that he adopted in his approach to chemical phenomena. Furthermore, transformation was a key motif of baroque aesthetics, and of the taste for mythological marvels on display in the Calvinist Netherlands: there again, we have Spinoza's scorn. Finally, the seventeenth century bore witness in England to the first great modern attempt at political transformation – and Spinoza was pessimistic.