One of us [Gilbert, M.. “Collective Belief and Scientific Change.” Sociality and Responsibility. Lanham, MD: Rowman & Littlefield. 37-49.] has proposed that ascriptions of beliefs to scientific communities generally involve a common notion of collective belief described by her in numerous places. A given collective belief involves a joint commitment of the parties, who thereby constitute what Gilbert refers to as a plural subject. Assuming that this interpretive hypothesis is correct, and that some of the belief ascriptions in question are (...) true, then the members of some scientific communities have obligations that may act as barriers both to the generation and, hence, the fair evaluation of new ideas and to changes in their community’s beliefs. We argue that this may help to explain Thomas Kuhn’s observations on “normal science”, and go on to develop the relationship between Gilbert's proposal and several features of a group of physicists working on a fundamental physical theory called “string theory”, as described by physicist Lee Smolin [Smolin, L.. The Trouble with Physics. Mariner Books: New York.]. We argue that the features of the string theory community that Smolin cites are well explained by the hypothesis that the community is a plural subject of belief. (shrink)