This essay is a study of Vvedenskij's works starting from his 1888 dissertation up to the turn of the century. I attempt to show that although his explicit aim was to update Kant's philosophy of science in light of developments in physics in the 19th century, Vvedenskij departed considerably from Kant's position with respect to both first philosophy and reflection on the achievements of the natural sciences. Vvedenskij's increasing concern with practical philosophy in the 1890s led him to correct a perceived anomaly in Kant's position by postulating a time in itself, an unrecognized consequence of which would be to undermine the apodicticity of mathematics.