The purpose of this article is to demonstrate that the experience of a poem qua poem is an experience of poetic thickness, i.e. an experience in which poetic form and poetic content are inseparable. I present a critical analysis of A. C. Bradley’s ‘Poetry for Poetry’s Sake’ lecture in Section 1, indicating both the strengths and weaknesses of his conception of resonant meaning. Section 2 draws on subsequent work by I. A. Richards and Peter Lamarque to advance my account of the relationship in question, poetic thickness, understood as a demand made of a poem rather than a property discovered therein. In Sections 3–6 I discuss four objections to form-content unity from Peter Kivy: perfect circularity, ubiquitous unity, the sugar-coated pill tradition, and the defence from tradition. I show that all these objections fail against poetic thickness. I conclude that the experience of a poem qua poem is indeed an experience of thickness, and that poetic thickness is therefore a necessary condition of poetry.