Tim Button explores the relationship between words and world; between semantics and scepticism. A certain kind of philosopher-the external realist-worries that appearances might be radically deceptive; we might all, for example, be brains in vats, stimulated by an infernal machine. But anyone who entertains the possibility of radical deception must also entertain a further worry: that all of our thoughts are totally contentless. That worry is just incoherent. We cannot, then, be external realists, who worry about the possibility of radical deception. Equally, though, we cannot be internal realists, who reject all possibility of deception. We must position ourselves somewhere between internal realism and external realism, but we cannot hope to say exactly where. We must be realists, for what that is worth, and realists within limits. In establishing these claims, Button critically explores and develops several themes from Hilary Putnam's work: the model-theoretic arguments; the connection between truth and justification; the brain-in-vat argument; semantic externalism; and conceptual relativity. The Limits of Realism establishes the continued significance of these topics for all philosophers interested in mind, logic, language, or the possibility of metaphysics.