If the European Enlightenment did not invent the idea of imagination, it certainly brought it to its fullest articulation, broadening its reach to include not only literature and the arts, along with philosophy and theology, but also political and social theory and even science. It became during the eighteenth century, in short, a crucial tool in virtually every area of intellectual life.
Until this time, intellectual inquiry had tended to focus on humankind's relationship with God, with nature, and with others. Thinkers like Thomas Hobbes (1588–1679), however, began to look inward, to consider the processes of human perception, the psychological dimensions of human experience, bringing to bear the empirical method that was to become increasingly important throughout the eighteenth century. Imagination for Hobbes was an active, creative faculty, not a mere passive receiver of impressions; it is the power that shapes our thoughts and sense impressions into unity, even into a coherent view of the world. Even John Locke (1632–1704), however much he might deplore imagination as "illusory," emphasized the unifying activity of the mind; later, David Hume (1711–1776), for all his skepticism, viewed the imagination as the power that brought together thought and feeling. Clearly the way was being paved for later thinkers like Coleridge, who would see imagination as the unifying power in human perception and creativity.
Even as Hobbes pushed forward the "Aristotelian" dimensions of imagination, probing the processes of the mind, his contemporary Shaftesbury (Anthony Ashley Cooper, 3rd Earl of Shaftesbury, 1671–1713) emphasized the Platonic heritage. Standing in the line of sixteenth-century Cambridge Platonists like Henry More and Ralph Cudworth, he also returned to the works of Plato and his Neoplatonic successors. While Hobbes focused on empirical knowledge, Shaftesbury was interested in the human grasp of the ideal and of spiritual reality. The result, at least for British intellectual history, was a richly balanced legacy for the Romantic thinkers who followed.
But the influence of Hobbes and Shaftesbury, along with that of other English and Scottish philosophers, reached far beyond England. Shaftesbury was introduced into Germany by Gottfried Wilhelm von Leibniz (1646–1716) and remained a lasting influence there throughout the eighteenth century, while the empiricist psychology of Hobbes, Locke, and others was eagerly welcomed in the German universities.
The two great thinkers on imagination in Germany are Johannes Nikolaus Tetens (1736–1807) and Immanuel Kant (1724–1804), who "stand like two colossi in their concepts of imagination" (Engell, p. 118). The contribution of Tetens, under the influence of the Scottish philosopher Alexander Gerard (1728–1795), was to widen the scope of imagination to make it central in all human perception, from the immediacy of sense perception to the complex creative act of the artist, thus laying the groundwork for what would later become Coleridge's distinction between primary and secondary imagination. Tetens was also insistent, as later Romantic theorists would be, that imagination is as crucial for the scientist and the philosopher as for the poet or painter.
Kant's role in the development of the idea of imagination, under the influence of Tetens, was to synthesize two currents of thought, reflecting the ancient tension between Platonic and Aristotelian views of the world: an idealist strain deriving from such thinkers as Leibniz, Christian von Wolff (1679–1754), Shaftesbury, Baruch Spinoza (1632–1677), and Friedrich Jacobi (1743–1819), and the more empirical line of Hobbes, Locke, Hume, and other British empiricists (see Engell, p. 128–29). Although he never clarified his thought to his own (or indeed to anyone else's) satisfaction, Kant's more transcendentalist analysis of imagination in the second edition of the Critique of Pure Reason and later in the Critique of Judgment is centrally important for the emerging Romantic period, in that Kant never lost sight of the role of objective perception even as he emphasized the formative and productive power of the human mind. Although he will use different terms for it (Einbildungskraft, Phantasie) and although the balance shifts throughout his life, imagination in Kant brings together with considerable success the sensible and the ideal worlds, the empirical and the transcendent.