The mind has greater power over the emotions and is less subject thereto, in so far as it understands all things as necessary.
Spinoza, Ethics, V
It is thoroughly established that Baruch Spinoza drew on the work of his predecessor Rene Descartes when he assembled his philosophy. What is most often put in the centre of this assumption is the way Spinoza sought to reaffirm Descartes’ system through a geometrical — and therefore, as it was thought at the time, indefeasible — superstructure.
The full extent of Descartes’ influence on Spinoza becomes clear when we turn to the Ethics. Descartes held that there is a division between our biological nature — which is wholly subject to deterministic relations — and our spirit, which is exempted from such determinism. There is a logical insufficiency at work here: if it were so that our spirit is wholly outside the biological machinery, how are we to explain that the spirit cannot withdraw its body from the iron-laws of nature?
It is in response to such questions that Spinoza would mould his refinement of Descartes. To Spinoza it isn’t so much that the mind — which is what the spirit receives as its reformulation — is singular in its exemption from iron-cast determinism, but that we can become conscious of determinism, and that this raising to the level of consciousness is what enable us to withdraw from the biological machinations of nature.
Spinoza upends Descartes’ absolute division between nature and spirit: rather, it is the extent to which the mind apprehends its situation in a domain of necessity that indicates our ability to command our emotions. We are reminded of Schopenhauer’s’ later wisdom: “to obtain something we have desired is to find out that it is worthless; we are always living in expectation of better things.”
To desire is to be dissatisfied, and to be able to regard one’s desire as transitory is our only source of tranquillity.