Ever since The Iliad and The Odyssey were ascribed to Homer, the blind poet has served as a metaphor for the ability to catch sight of things beyond mere appearance. Robert Duncan, born in 1919, belonged to this tribe of seers. At the age of 3, he slipped in the snow in Yosemite while wearing sunglasses against the glare; they shattered, and the injury resulted in strabismus—a condition in which the eyes cannot focus on the same object.