This dissertation explores how modernists envisioned thinking, judging, and acting in conditions of paradox. I hold modernism up against historical developments in logic, mathematics, and analytic philosophy to argue that T.S. Eliot, Robert Frost, Gertrude Stein, and I.A. Richards generated distinctive aesthetic, phenomenological, and affective responses to paradoxical situations. I anchor the work of these modernists in twentieth-century intellectual contexts with which they were all familiar, including the transition out of classical logic into a supposedly unparadoxical new symbolism; the waning of idealism and subsequent waxing of analytic philosophies; and the drive to “complete” mathematics. I demonstrate how modernists drew from these contexts the overarching problem of the liar paradox, whose paradoxical self-reference resisted all of logic’s attempts to resolve it. Articulating an aesthetics of paradox that is shaped by, yet often resistant to, these nascent new philosophies that were themselves defined by the liar paradox, modernists attend to the lived consequences, stylistic repercussions, and emotional tonalities of judging and acting in paradoxical situations. I argue that they bear witness to logic’s struggles against paradox with profound consequences for narrative, poetics, form, and style. And I claim that they deepen approaches to logical thinking with a focus on what self-reference looks and feels like as an aesthetic experience: on paradoxes that link stylistic fragmentation with bodily harm (Eliot); self-referential structures that model human suffering (Frost); circular predicates that mimic processes of thought (Stein); and the metalinguistic consequences of self-reference in the context of close reading (Richards). Affective and stylistic dimensions of paradox mediate between the scales of concept, art, and intellectual history: Eliot’s poetic illusions and hallucinations emerge from grammatical self-reference and a graduate-level study of logic; Frost’s depictions of marital strife root in “unvicious circles” that mirror ones Frost studied at Harvard; Stein’s drive to capture consciousness in a totalizing self-referential style carries on a mathematical dream of completeness learned from A.N. Whitehead; and Richards’s metalinguistic project borrowed from logic to develop many of the formalist tools that literary scholars use to this day. Throughout I draw connections between these aesthetic presentations of paradox and our current literary practices, offering updated accounts of inference, evidence, figuration, and especially form—as logical concept, linguistic quodlibet, literary-critical object, and stylistic protocol.