Phenomenology begins with the discussion of naturalism, being conceived as a critical response to naturalism. In 1910/11 Edmund Husserl, the founder of phenomenology, plans a “rigorous science” (strenge Wissenschaft) but dismisses naturalism. Martin Heidegger, his student, talks in his first lectures in Freiburg, 1919, 1920 about Urwissenschaft (56/57) and Ursprungwissenschaft (58) (both originary science), most certainly influenced by Husserl, and holding for the same idea of questioning natural sciences and their relevance in philosophy. The very core of phenomenology, both transcendental and hermeneutical, seems to be incompatible with naturalism: transcendental versus empirical, understanding versus knowing (Erkenntnis). However, recently a vivid debate on phenomenology and naturalism came up, mainly discussing “naturalizing phenomenology”. Nevertheless, there are good reasons why phenomenology and naturalism cannot be reconciled: I will briefly show why a reconciliation would not work for Husserl who dismisses the “empirical evidence” and why it would not work for Heidegger, who conceives science as objectification.