Objectivity in science is an attempt to uncover truths about the natural world by eliminating personal biases, emotions, and false beliefs. It is often linked to observation as part of the scientific method. It is thus intimately related to the aim of testability and reproducibility. To be considered objective, the results of measurement must be communicated from person to person, and then for third parties, as an advance in a collective understanding of the world. Such demonstrable knowledge has ordinarily conferred demonstrable powers of prediction or technology. The problem of philosophical objectivity is contrasted with personal subjectivity, sometimes exacerbated by the overgeneralization of a hypothesis to the whole. For example, Newton's law of universal gravitation appears to be the norm for the attraction between celestial bodies, but it was later refined and extended—and philosophically superseded—by the more general theory of relativity. History The scientific method was argued for by Enlightenment philosopher Francis Bacon, rose to popularity with the discoveries of Isaac Newton and his followers, and continued into later eras. In the early eighteenth century, there existed an epistemic virtue in science which has been called truth-to-nature. This ideal was practiced by Enlightenment naturalists and scientific atlas-makers, and involved active attempts to eliminate any idiosyncrasies in their representations of nature in order to create images thought best to represent "what truly is". Judgment and skill were deemed necessary in order to determine the "typical", "characteristic", "ideal", or "average". In practicing, truth-to-nature naturalists did not seek to depict exactly what was seen; rather, they sought a reasoned image. In the latter half of the nineteenth-century, objectivity in science was born when a new practice of mechanical objectivity appeared. Let nature speak for itself' became the watchword of a new brand of scientific objectivity." It was at this time that idealized representations of nature, which were previously seen as a virtue, were now seen as a vice. Scientists began to see it as their duty to actively restrain themselves from imposing their own projections onto nature. The aim was to liberate representations of nature from subjective, human interference and in order to achieve this scientists began using self-registering instruments, cameras, wax molds, and other technological devices. In the twentieth century trained judgment supplemented mechanical objectivity as scientists began to recognize that, in order for images or data to be of any use, scientists needed to be able to see scientifically; that is,