  The philosophical discipline of aesthetics did not receive its name until 1735, when the twenty-one year old Alexander Gottlieb Baumgarten introduced it in his Halle master’s thesis to mean epistêmê aisthetikê, or the science of what is sensed and imagined (Baumgarten, Meditationes §CXVI, pp. 86–7). But Baumgarten’s denomination of the field was an adult baptism: without a name, aesthetics had been part of philosophy since Plato attacked the educational value of poetry in the Republic and Aristotle briefly defended them in his fragmentary Poetics. In particular, Aristotle defended poetry from Plato’s charge that it is cognitively useless, trading in mere images of particulars rather than universal truths, by arguing that poetry delivers universal truths in a readily graspable form, unlike, for example, history, which deals merely with particular facts (Aristotle, Poetics, chapter 9, 1451a37–1451b10). And if experience of poetry can reveal important moral truths, then it can also be important to the development of morality, the other pole of Plato’s doubts. Some variant of this response to Plato was the core of aesthetics through much of subsequent philosophical history, and indeed continued to be central to aesthetics through much of the twentieth century. In the eighteenth century, however, two alternative responses to Plato were introduced.  One may be regarded as taking up Aristotle’s idea in the Poetics that “katharsis,” purification or purgation, of the emotions of fear and pity, is a valuable part of our response to a tragedy; this led to an emphasis on the emotional impact of aesthetic experience that was downplayed in the cognitivist tradition. This line of thought was emphasized by Jean-Baptiste Du Bos in his Critical Reflections on Poetry, Painting, and Music, published in France in 1719 and widely known throughout Europe even before it was translated into other languages. The other innovation was the idea that our response to beauty, whether in nature or in art, is a free play of our mental powers that is intrinsically pleasurable, and thus needs no epistemological or moral justification, although it may in fact have epistemological and moral benefits. This line of thought was introduced in Britain in Joseph Addison’s 1712 Spectator essays on “The Pleasures of the Imagination,” and developed by subsequent Scottish writers such as Francis Hutcheson, Henry Home (Lord Kames), and Alexander Gerard. It was only slowly received in Germany, hinted at by Moses Mendelssohn in the late 1750s, who also took up Du Bos’ emphasis on the emotional impact of aesthetic experience, but then made its first sustained appearance in the emphasis on the pleasure of the unhindered activity of our powers of representation in some of the entries in Johann Georg Sulzer’s Allgemeine Theorie der schönen Künste (1771–74), e.g., the entries on “beauty” and “taste” (Sulzer, Allgemeine Theorie, vol.  II, pp. 371–85, at p. 371, and “Schön (Schöne Künste),” vol. IV, pp. 305–19, at p. 307). It became central to the aesthetic theories of Kant and Schiller in the Critique of the Power of Judgment (1790) and the Letters on the Aesthetic Education of Mankind (1795). This article will chronicle the interaction between the traditional theory of aesthetic experience as a special form of the cognition of truth and the newer theories of aesthetic experience as a free play of cognitive (and sometimes other) mental powers and as a vicarious experience of emotions in eighteenth-century Germany.