The word ‘pseudoscience’ is a marker of changing worries about science and being a scientist. It played an important role in the philosophical debate on demarcating science from other activities, and was used in popular writings to distance science from cranky theories with scientific pretensions. These uses consolidated a comforting unity in science, a communal space from which pseudoscience is excluded, and the user's right to belong is asserted. The urgency of this process dwindled when attempts to find a formal demarcation petered out, and the growth of social constructionism denied science any special access to truth. The reaction to this led to the science wars, which ushered in a new anxiety in the use of ‘pseudoscience’, especially from the least secure branches. But recent writings on the disunity of science reveal how the sense of support drawn from it may be based on an illusion, creating a disunity of pseudoscience as well as of science.