The History and Significance of Hume’s Burning Coal Example: Time, Identity, and Individuation

This paper examines the function of Hume’s use of a peculiar example from A Treatise of Human Nature. The example in question is that of a burning piece of coal that is whirled around at a sufficient speed to present to a viewer an image of a circle of fire. The example is a common one; and Hume himself points to Locke as his source in this case. Hume’s reference appears accurate since both Locke and Hume seem to marshal the example in order to bolster a case for an upper and lower temporal threshold for perception. But several philosophical problems inherent in Hume’s appeal to the example make the case for Locke as Hume’s sole or even primary source difficult to sustain. The paper sketches a history of uses of the example from the seventeenth century through the twentieth century. An argument is presented that Pierre Bayle’s use of the example is most in accord with Hume’s, and that for this and other reasons, Bayle is his likeliest source. Further, making sense in this way of Hume’s use of the burning coal example illuminates Hume’s interesting contributions to the notions of time, identity, and individuation