 Although it is mainly speculation, there is reason to believe that the person Locke referred to was the mathematician and scientist Nicholas Saunderson, who held the Lucasian professor chair at Cambridge University, and whose general prominence would have made his statements noticeable.In "Letters on the blind", Denis Diderot, one of Locke's followers, mentions Saunderson by name in related philosophical reflections.In 1710, Thomas Woolhouse reported the case of another blind man who perceived colors in response to sounds.