In this article from 1928, translated here for the first time, Tanabe Hajime examines the concept of self-evidence, mainly in the light of Husserl and Brentano. The author starts out by establishing, through a preliminary analysis of the Cartesian cogito, two criteria for self-evidence, namely adequate fulfillment of the intention of Sosein, and the coextension of Dasein and Sosein (being-there, or existence, and being-such, or essence/properties). He then proceeds to consider four domains of knowledge through the prism of the question of their claim to self-evidence: knowledge of mathematical objects, categorial intuition, the ontological proof for the existence of God and finally, outer perception. Dedicating the last paragraph to a critical assessment of Husserl’s account of perception, the author concludes that all self-evidence is founded on inner perception. Outlining a creative appropriation of phenomenology while elucidating the conditions for certainty, this text constitutes an important milestone in a period leading up to Tanabe’s break with Nishida as well as to his critique of Heidegger, thus laying the groundwork for his independent philosophical stance.