Leibniz believed the ‘true concept of substance’ is found in ‘the concept of forces or powers’. Accordingly, he conceived monadic substances as metaphysically primitive forces whose modifications manifest both as monads’ appetitions and perceptions and as derivative forces in monads’ organic bodies. Relationships between substances, and in particular the ethical relationships that hold between rational substances, are also foregrounded by Leibniz’s concept of substances as forces. In the first section of this paper, we discuss the derivative forces of bodies. In section two, we turn to discussion of the monads’ perceptions and appetitions. Section three attends to ethical implications embedded in Leibniz’s account, focusing in particular on souls’ representative natures and the correspondence that obtains between the perceptions in one and the perceptions in all others. In the fourth and final section, however, I argue that Leibniz’s commitment to the doctrine of the conservation of force makes it impossible for any one substance to pursue its own advantage by increasing its active force without there being a correlative disadvantageous decrease in the active force of substances elsewhere in the universe. While the reconciliatory proposals offered do not entirely remove the tension between Leibniz’s ethics and his physics, they do soften its severity and allow it to be regarded in a more positive light.