Since the rise of scientific thinking in the seventeenth century the role of the imagination in literature has been a matter for debate. Is it an essential resource, or a treacherous purveyor of illusions? In this lecture Professor Beer suggests that one result of this uncertainty has been to set up a divison (which continues to pervade literary enterprises) between imaginative flights on the one hand and the "weighing of words" on the other. His examples are drawn from a wide range of writers, including Johnson, Dickens, Hopkins, Woolf and Wordsworth.