The phrase "mutual construction" highlights the common conception of science as a group endeavor. Indeed, one of the ways to view science is as an ever-growing body of theories and facts, empirically verified and subject to peer criticism. It is this definition as a body of knowledge that is one of the core values of science — it discourages scientists from claiming ownership of their contributions. Scientific knowledge is essentially public and commonly shared knowledge (an ideal which Merton has described as Communism in the CUDOS model) and the way it is constructed is via the mutual efforts of scientists all over the world who build upon each other's work. Incidentally, this is also why priority is so important for scientists, in a world where all knowledge is common property (and there are no patents), recognition is the only mechanism via which their work is validated.

"Co-production" on the other hand highlights another important aspect of science, the fact that it does not operate in a vacuum so to speak. Contrary to what the Mertonian ideals of organized skepticism and universalism might suggest, mainstream scientific work is more often than not a dialectic between the needs and interests of society and the interests of science. To elaborate, what passes for acceptable scientific work is more often than not determined by external factors (just consider the example of cold fusion), and in particular topics that scientists choose to work on are often determined by the needs of society (multiple examples come to mind, especially in computing and the like — driven mostly by military needs — the need to compute missile trajectories etc). Science in turn affects society — so that the duo form a sort of feedback loop.