In the middle decades of the nineteenth century objectivity established itself as a (if not the) cardinal epistemic virtue in the sciences. From astronomy to paleontology to physiology, new ways of making images, assessing error, and designing experiments were enlisted in the service of objectivity. This triumph of objectivity over rival epistemic virtues like truth and certainty is all the more remarkable because objectivity had emerged only decades before. Only around 1850 did the modern sense of "objectivity" make its way into dictionaries in the major European languages. The ideals and practices associated with objectivity in the sciences emerge at roughly the same time.
The story of how objectivity became so central to science is one of actions as well as words. Objectivity changed how science was done in concrete, specific ways. Photography, self-registering instruments, the method of least squares, and machines for measuring the personal equations of observers were all examples of these new scientific practices of objectivity, which this project sought to investigate.