This paper discusses Nietzsche's critique of causality, as one of the central concepts of science, under the aspect of his physiological thinking. Causality is not of course the only concept Nietzsche problematises as part of his comprehensive critique of scientific and metaphysical conceptuality — substance, subject, telos and the concept of scientific law, for instance, could also be mentioned. But Nietzsche's critique of causality occupies a central role in his attempt to envisage an affirmative type of science, as opposed to the reductive, nihilistic conceptuality which he saw to be dominating the science of his day and which is still largely operative today. At certain points throughout the essay, Kant's philosophical foundation of natural science in the Critique of Pure Reaso ¹ is taken as the paradigm of a philosophy imbued with unacknowledged metaphysical values against which Nietzsche's type of critique is directed.