This essay aims to retrace the varied influences of Henri Poincaré’s ideas on the thought of Joachim Metallmann (1889-1942). Metallmann was a Polish Jew who was murdered by the Germans during World War II and has largely been neglected in the West. Metallmann’s philosophy of science inspired by figures like A. N. Whitehead and H. Poincaré was contrary to the positivistic and logicistic trends dominant in Poland in his time, veering towards a metaphysical reflection on nature. The influences of Poincaré’s (...) work can be found throughout Metallmann’s major works. My intention is to show how Metallmann’s idea of emergentism is quite probably based on Poincaré’s theory of nonlinear dynamical systems. Moreover, the structuralist tendencies of Metallmann’s thought can be linked to Poincaré’s ideas. This all proves that Poincaré’s impact on the philosophy of science goes beyond his role as a “father of conventionalism.”. (shrink)