When the incidence of a condition called "morgellons" seemed to be increasing, the centers for disease control (cdc) conducted research that found no evidence of such infections actually taking place. soon after, the mayo clinic in minnesota conducted similar research and obtained nearly identical findings. as it turned out, most people who thought they had morgellons had very simple skin conditions, or no condition at all. the repetition of the cdc's research that was used to support the findings is crucial to critical thinking, in a principle called