The paper discusses the value of science in the context of the crisis that Western civilization is going through, and indicates some of the implications of the proposed analysis for the issue of teaching. Firstly the distinction is established between pure and instrumental science, then a study is made on the impact of specialization upon the value of pure science. With the aim of assessing the contribution of science to the satisfaction of human beings' basic needs, a second distinction is introduced, between basic and applied science. The final section proposes that the critical spirit prevalent inside the practice of science is to be extended to the reflection about that practice.