In 1930 W. B. Yeats dictated a letter to George Moore, advising him to eat salt: salt was "the symbol of eternity" and its consumption vouchsafed one's longevity. 1 Yeats was delirious from fever when he offered Moore his medical opinion, yet the advice reveals some of the poet's most strongly held convictions: first, that reality-even in salt form-is intrinsically symbolic; second, that symbols participate in what they depict (salt is a morsel as much as it is a sign of eternity); third, that symbols have practical or therapeutic results (despite what the medics might say, salt is good for you). Indeed, the world-altering effects of the symbol allowed art to operate as a kind of magic. Yeats's views on symbolism may seem idiosyncratic, but they depend on a number of philosophical and theological traditions in which he was deeply immersed. The aim of this essay is to examine these traditions in order to determine why the symbol became such a "troubled mirror" in Yeats's work. 2 More broadly, I hope to recover some of the intellectual excitement of symbolism both as a practice and as a theory and to show how this excitement is lost when the study of literary form is removed from a broader philosophical history-the metaphysical character of which many scholars might feel they have outgrown.The symbol, as we shall see, is a metaphysically overburdened conceptindeed, Heidegger maintained that it carries the whole of western metaphysics on its back. 3 This partly explains why traditional lore about symbolism can be something of an embarrassment for "postmetaphysical" folk or for those who aspire to this disenchanted condition. 4 So while René Wellek could produce a confident set of reflections on symbolism for New Literary History in 1970-and theories of the symbol were central to literary criticism for figures like Northrop Frye-this is no longer where the critical conversation predominantly resides. 5 Symbolism, it might seem, is another species of white mythology: a mystified account of signs derived from a metaphysical account of being that should be left quietly to die. 6 The option of a quiet death was never possible when Derrida was around: after all, he was fascinated by the idea of metaphor (of which symbol is a subset), but his conclusion that it was an essentially "metaphysical concept" could read like an indictment in the face of his broader, albeit ambiguous, critique of metaphysics. 7 For born-again