This study aims to examine the thoughts of fourth-year pre-service science teachers about the nature of science. For this purpose, the study preferred the qualitative research method and phenomenology design. Participants consisted of nine pre-service science teachers. Participants wrote a self-evaluation report after the nature of the science course. I collected data with this report and focus-group interview. I did the data analysis using content analysis. The current study discusses validity and reliability. As a result of the analysis, pre-service science teachers stated that they learned the nature of science by adopting the constructivist philosophy. Therefore, they described that they will use the constructivist scientific language when they become teachers in the future. They argued that students should learn how scientific knowledge changes and develops. In addition, pre-service science teachers emphasized that teachers should direct their students' learning processes according to the constructivist philosophy considering scientists' culture, beliefs, and prior knowledge. They stated that students should understand the socio-cultural impact on the learning process. They also mentioned that students should use their imagination and creativity so that they can learn scientific information meaningfully. Based on these results, I suggested that teaching based on positivist philosophy would not remove the obstacles to students' learning science.