Georg Christof Lichtenberg was a major figure in 18(th) century physical science, well known for his lectures to students as well as his scientific achievements. In addition, he was an active and enlightened humanist who engaged on the liberal side of debate of many contemporary issues, although the aphorisms and letters for which he is now famous were largely discovered and published posthumously. Among his interests was color vision and he became engaged with Goethe in an exchange concerning 'coloured shadows.' Goethe Sailed to obtain support from Lichtenberg, whose careful empirical approach to the topic did not find much appeal in Goethe's ideas. The exchange between the two provides an interesting sidelight on one of the issues of color vision in the 18th century. (C) 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S28-S31, 2001.