Collecting the work of linguists, psychologists, neuroscientists, archaeologists, artificial intelligence researchers and philosophers this volume presents a richly varied picture of the nature and function of mental states. Starting from questions about the cognitive capacities of the early hominin homo floresiensis, the essays proceed to the role mental representations play in guiding the behaviour of simple organisms and robots, thence to the question of which features of its environment the human brain represents and the extent to which complex cognitive skills such as language acquisition and comprehension are impaired when the brain lacks certain important neural structures. Other papers explore topics ranging from nativism to the presumed constancy of categorization across signed and spoken languages, from the formal representation of metaphor, actions and vague language to philosophical questions about conceptual schemes and colours.