"Spinoza’s metaphysics does not ground human identity in the basic metaphysical constitution of things: a human being is not an independent substance and cannot be individuated by its real distinction from all else. The human mind is constituted by its affects, which insofar as they are active, and thus proper to the mind itself, work to preserve its being, and increase its power of action. Still, it is always dependent on and susceptible to what is outside it. Something similar can be said for bodies too; they are not substantially differentiated from the rest of the extended universe with which they interact and on which they depend. But Spinoza’s parallelism (or ‘equalism’) means that an alternative, less substantial account of how we individuate the human body can capture mental identity in the same net. Spinoza provides such an account in his understanding of how the bodily activity of the affects preserves the relations and boundaries of our bodies, particularly the proportion of motion and rest crucial to bodily identity and life. So, the active affects maintain identity – the identity on which they depend – by negotiating what systems theory calls a “systems-environment boundary.” It is perfectly consistent with the dynamically achieved identity of body, mind, and human being, however, that we might take on yet other identities, identities that may be equally important to us and equally ‘ours.’ For instance, Spinoza sometimes speaks of the society common to all humans as a body seeking to preserve its own boundaries and proportions of motion and rest, something that would give a physical grounding to collective identity. Then too, insofar as we approach beatitude and the intuitive knowledge of the whole, we may take on an identity approaching to the identity of the whole, becoming more and more like God. These remain mere speculations, though, unresolved in Spinoza’s work. Indeed, some of the puzzling passages at the end of Part V appear torn between whether we should seek to “merge” our individual mind with God or to preserve its distinctive identity within the field of different, external, and sometimes competing forces''.

11. Influences on Later Authors

Although both Leibniz and Hume take issue with different features of his metaphysics, Spinoza’s approach to the passions seems to have exerted relatively little direct influence on his contemporaries. There are similarities, of course: Hume complicates the understanding of our psychological associations and how they can be transmitted socially in ways not unlike Spinoza. Hume also talks about the mechanisms by which we generate prejudices, although he will find their source more in the causal associations of the imagination than in the passions. But there is little evidence that these are anything more than similarities, especially since Hume’s knowledge of Spinoza was transmitted largely through Bayle. It may be that Spinoza’s approach to the emotions is so closely intertwined with the whole of his system that it is difficult to appropriate piecemeal, and so remains sui generis. On the other hand, Spinoza was to become an important figure for nineteenth-century philosophers, most notably for Friedrich Nietzsche. In 1881, Nietzsche wrote his friend Overbeck that he was “astonished” and “utterly enchanted” to find in Spinoza a precursor insofar as they both tend “to make knowledge [Erkenntnis] the most powerful affect” (Nietzsche 1976, 92, translation slightly altered). Nietzsche later singles out Spinoza’s treatment of pity for praise in the Genealogy of Morals (1887). More generally, his understanding of the will to power shares a great deal with Spinoza’s understanding of our affective drive, although whether this is a matter of direct influence or what Nietzsche might call a common “instinct” is arguable.

https://plato.stanford.edu/entries/emotions-17th18th/LD5Spinoza.html#:~:text=The%20human%20mind%20is%20constituted,to%20what%20is%20outside%20it.