Work partially supported by the Portuguese Science Foundation, FCT, through the projects The Notion of Mathematical Proof, PTDC/MHC-FIL/5363/2012, Hilbert’s 24th Problem, PTDC/MHC-FIL/2583/2014, and the Centro de Matemática e Aplicações, UID/MAT/00297/2013.This paper provides a discussion to which extent the Mathematician David Hilbert could or should be considered as a Philosopher, too. In the first part, we discuss some aspects of the relation of Mathematicians and Philosophers. In the second part we give an analysis of David Hilbert as Philosopher.authorsversionpublishe