In our last chapter we saw that Nietzsche's metaphysics can be understood as a response to deficiencies in the Kantian system. According to Nietzsche, Kant fails to capture the nature of real causal efficacy, and central to Nietzsche's response to Kant is his proposal of the will to power thesis, which holds that empirical powers are causally efficacious because they are metaphysically real. Controversially proposing a metaphysics that understands the ultimate constituents of empirical reality as both relational and intrinsic, the will to power thesis represents the final step in Nietzsche's overcoming the metaphysics of opposites with which we began our investigation in chapter 1, particularly the opposition between self and world Nietzsche detects in Kant. Pivotal to Kant's separation of self and world, according to Nietzsche, is the disconnection between relational empirical reality and intrinsic natures obtaining at the level of things-in-themselves. Therefore, the ultimate success of Nietzsche's overcoming the opposition of self and world rests on the philosophical coherency of his aim to house intrinsic natures within the relational sphere of the empirical world.

In light of the importance of Nietzsche's metaphysics, this chapter extends our analysis of the will to power beyond the confines of its Kantian context in order to consider the philosophical cogency of Nietzsche's argument in favour of the reality of causal powers, a proposal that has been subject to a fundamental objection. The objection claims that the will to power thesis contains two incompatible aspects.