How to create a philosophy thesis relating to a design project? How to approach more widely the epistemological juxtaposition of design and philosophy? This paper examines a pedagogical design research methodology experiment called ‘philosophy applied to design’, implemented over 8 years in a French art and design school at Master’s level, and based on the supervisory experience of more than 220 philosophy theses applied to a design project (sections 1 & 2). It addresses a series of methodological and epistemological questions on the association between philosophy and design and presents the methodological model developed during the experiment (section 3). This model is used as a basis for defining a new philosophy-oriented design research called ‘philosophy by design’ (section 4). — Highlights : 1, I explain how to create a philosophy thesis relating to a design project. 2, I examine a supervisory experiment of more than 220 philosophy theses. 3, I address epistemological issues on the encounter of design and philosophy. 4, We must teach the difference between a project question and a philosophical one. 5, I try to define a new design research model as ‘philosophy by design’.