Bernays’s philosophical thought evolved from L.Nelson’s and J.F.Frics’s epistemological outlook to Gonseth’s open epistemology (from the Kantian doctrine to open phenomenology). The paper is divided into two parts. The first part deals with philosophical inspirations and the evolution of Bernays’ metascientific outlook. The second part considers his epistemological views from the period of inspiration by Gonseth’s open philosophy. It is the final, mature stage of Bernays' evolution that is important for mathematical epistemology.