  Hacking also discussed the strengthening of one’s belief in an observation by independent confirmation. The fact that the same pattern of dots—dense bodies in cells—is seen with “different” microscopes, (e.g. ordinary, polarizing, phase-contrast, fluorescence, interference, electron, acoustic etc.) argues for the validity of the observation.  One might question whether “different” is a theory-laden term. After all, it is our theory of light and of the microscope that allows us to consider these microscopes as different from each other. Nevertheless, the argument holds. Hacking correctly argues that it would be a preposterous coincidence if the same pattern of dots were produced in two totally different kinds of physical systems. Different apparatuses have different backgrounds and systematic errors, making the coincidence, if it is an artifact, most unlikely. If it is a correct result, and the instruments are working properly, the coincidence of results is understandable.