The article considers two critical ontological ideas of Nietzsche - anti-essentialism and criticism of causality. Nietzsche's anti-essentialism serves as the main basis for his criticism of metaphysical ontology based on the idea of identity. The first part of the article presents an analysis of Nietzsche's anti-essentialism. It shows that anti-essentialism runs through all of Nietzsche's works, from early ones, for example, "On Truth and Lies in a Nonmoral Sense", to the late stage of his works. Criticizing various kinds of "unity", for example, the concept "atom", Nietzsche eventually comes to the denial of the concept "thing". Based on this, such concepts as "subject" and "soul" are also criticized. The second part of the article examines Nietzschean criticism of causality or causalism. It, like anti-essentialism, also runs through all of Nietzsche's works, from his early works to the handwritten legacy of the last years of his conscious life. Nietzsche's original arguments to the critique of causality are considered, and Nietzsche's agreement with Hume on this issue is shown. By criticizing the concept of the goal, Nietzsche, in fact, carries out the criticism of the target cause in Aristotle. After dealing with Nietzsche's main objections, the author shows the relationship between anti-essentialism and criticism of causalism. This relationship is embodied primarily in their structural parallelism, based on the same metaphysical leap. In addition, the similarity of Nietzsche's views on causality with modern physics is pointed out. Where the ideas of Werner Heisenberg, who also criticized causalism, are taken as an example. In his conclusions, the author points to the place of anti-essentialism and criticism of causality in Nietzsche's philosophy. It consists of two main consequences. Firstly, by criticizing causality and essentialism, Nietzsche breaks with the philosophical tradition that preceded him - metaphysics. Secondly, Nietzsche, proceeding from this criticism, comes to the formation of his own ontology, an alternative metaphysics of the Eleatics, an ontology of becoming.
