Sobol's chapter builds on the thesis that although medieval scholars inherited a theory of sensation based primarily on visual phenomena from Aristotle and his Islamic commentators, this had yet to be applied to sensation in general. Roger Bacon began the task of elucidating the nature of sensible species (the primary representations of sensible qualities) and their role in sensation, but it was Buridan who devoted a large part of his question commentary to demonstrating that both external and internal sensation relied on species. Buridan departed from Aristotle in asserting a finite speed of light, but on the other side he departed from most of his contemporaries, and remained faithful to Aristotle, by locating the organs of the common sense and the imagination in the heart instead of the head.