Piedmont University will host Professor Gabriel Ferreira of Brazil’s Unisinos University for a thought-provoking event titled You Can’t Untie a Knot You Don’t Know About: Some Remarks on Philosophy and Its History at 11 a.m. on Feb. 17 at the Arrendale Library on Piedmont’s Demorest campus. Ferreira is a philosophy professor at Unisinos and a…