Spinoza’s conatus doctrine, the main proposition of which claims, “[e]ach thing, to the extent it is in itself, strives [conatur] to persevere in its being” (E3p6), has been the subject of growing interest. This is understandable, for Spinoza’s psychology and ethics are based on this doctrine. In my paper I shall examine the way Spinoza argues for E3p6 in its demonstration which runs as follows: "For singular things are modes by which God’s attributes are expressed in a certain and determinate way (by 1p25c), i.e. (by 1p34), things that express, in a certain and determinate way, God’s power, by which God is and acts. And no thing has anything in itself by which it can be destroyed, or which takes its existence away (by p4). On the contrary, it is opposed to everything which can take its existence away (by p5). Therefore, to the extent it can, and is in itself, it strives to persevere in its being." This argument has been severely criticized for being defective in many ways.
E3p6d contains four items, E1p25c, 1p34, 3p4, and 3p5. Most often, only the two last mentioned are regarded as doing any real work in the demonstration. However, I shall argue that having a proper grasp of Spinoza’s concept of power enables us see that the demonstration’s beginning, built on E1p25c and 1p34, brings forth a certain dynamic framework in which finite things are centers of causal power, capable of producing effects in virtue of their essences. My examination of this framework shows the beginning of the demonstration to be irreplaceable: in the end, conatus is one form of power, and E1p25c and 1p34 not only bring the notion of power into play, but also inform us on how finite things’ power should be understood in the monistic system. So, I disagree with such commentators as Jonathan Bennett, Edwin Curley, Daniel Garber, Michael Della Rocca, and Richard Manning, who see Spinoza as trying to derive the conatus doctrine from E3p4 and 3p5 alone; and I agree with Alexandre Matheron, Henry Allison, and Martin Lin, who stress the importance of E1p25c and 1p34.
However, this still leaves us the task of reconstructing the whole derivation and showing how its various ingredients fit together. If E1p25c and 1p34 are so important, could E3p6 not be derived from them alone, as Martin Lin has argued? In other words, why are E3p4 and 3p5 needed at all? To answer these questions I shall provide an interpretation of E3p6d that explains how the argument is supposed to work. E1p25c and 1p34 say that finite things are, in essence, dynamic causers, which, in case of opposition, truly resist opposing factors with their power and do not simply cease their causal activities whenever facing obstacles; in other words, they strive against any opposition. However, this is not enough to guarantee that they could not act self-destructively or restrain their own power, which would make them incapable of self-preservation. But this would go against E3p4, “No thing can be destroyed except through an external cause,” and Spinoza uses it to claim, “no thing has anything in itself by which it can be destroyed, or which takes its existence away.” So all this allows Spinoza to hold that finite things are consistent causers, that is, entities endowed with power and, insofar they cause effects solely in virtue of their essence, they never use their power self-destructively.
The significance and role of the final item in the demonstration, E3p5 (“Things are of a contrary nature, i.e., cannot be in the same subject, insofar as one can destroy the other”), still needs to be determined. Indeed, considering its content and the way it is used in the demonstration, it seems to be a surprisingly decisive ingredient in the argument. Namely, what “each thing, to the extent it is in itself,” that is, insofar as any thing is considered disregarding everything external to it, strives to preserve, is its being (esse), not simply its present state. This together with E3p5’s view of subjecthood – which I shall explicate in my paper – suggests that we should rethink what kind of “being” or “existence” is meant in E3p6. Indeed, for Spinoza, each subject has a definable essence from which, as far as the subject in question is in itself, certain properties or effects necessarily follow; consequently a subject’s full being involves not only instantiating a certain essence, but also those properties inferable from the essence-expressing definition. Thus, E3p5 is meant to bring forward that things are not merely non-self-destroyers but subjects from whose definitions properties follow; and as Spinoza thinks to have shown (by E1p25c and 1p34) that finite modifications are entities endowed with power, any subject has true power to produce the properties or effects derivable from its definition, which, Spinoza claims, implies opposing everything harmful. In other words, things exercise power as their definition states, i.e. according to their definitions, and thus bringing in the idea of things as expressers of power enables Spinoza to convert logical oppositions (of E3p5) into real ones (of E3p6).
To summarize, Spinoza reasons that each true finite thing is, in itself, an expresser of power (E1p25c, 1p34) that never acts self-destructively (E3p4) but instead strives to drive itself through opponents to produce effects as they follow from the definition of the thing in question (E1p25c, 1p34, and 3p5). Therefore, “each thing, to the extent it is in itself, strives to persevere in its being.” The demonstration of E3p6 has its roots deep in Spinoza’s ontology, and since its concept of power is supposed to provide the metaphysical grounding for real opposition, the importance of E1p25c and 1p34 should not be underestimated just because Spinoza – as often happens – puts his point exceedingly briefly. Moreover, the derivation is basically valid and contains no superfluous elements. Finally, all this tells us something decisive about the meaning of Spinoza’s doctrine: according to it, things are active causers whose “power to exist and act” has conatus character in temporality, amounting not only to striving to prolong the duration of one’s actualization but also to striving to be as active or autonomous as possible, that is, to attain a state determined by the striving subject’s essence alone.