Figure 1. Title page of the 1811 edition of William Duncan's Elements of Logic, originally published in 1748
William Duncan (1711-1760) was a Scottish philosopher and Professor of Natural Science at Marischal College, Aberdeen, Scotland. In 1748 he published The Elements of Logic in Four Volumes, which became a popular text on the discipline of logic. This work was adopted in the early colleges of America. Thomas Jefferson, when he studied at William and Mary College (1760-1762), used Duncan’s Logic and later retained a copy of the work in his personal library. It is believed that its instruction may have influenced the composition of the Declaration of Independence (Golden & Golden, p. 47). The title page for the 1811 edition is shown above.
Figure 2. On page 143, Duncan considered the moral implications of argumentation.
Figure 3. Here on page 207 the author endorsed the study of algebra as a means to strengthen one's ability to think logically.
James Golden and Alan Golden, Thomas Jefferson and the Rhetoric of Virtue, Rowan & Littlefield, Landen, Maryland, 2002.
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