Critical thinking is widely regarded as one of the main objectives of education in general terms, and also of science education. The idea of thinking critically, that is, to evaluate adequately and eventually embrace a certain claim only if there are good reasons for it, however, seems to contradict some popular conceptions about other educational ideal: open-mindedness. The purpose of this essay is to discuss how critical thinking and open-mindedness are not exclusionary ideals, and how those ideas are important for science education.