Higher-Order Theories of Consciousness

Higher-order (HO) theories of consciousness hold that a mental state is conscious when it is appropriately represented by a ‘higher-order’ state, a state about another mental state. The higher-order perception (HOP) theory holds that HO representation is best modeled on perceptual processes, while the higher-order thought (HOT) theory holds that it is best modeled on thought. In addition, some HO theories hold that to be conscious, a state must be actively represented by an HO state, while others maintain that the mere disposition to be represented by an HO state is enough. The HO theory, if successful, offers a reductive explanation of mental state consciousness in terms of nonconscious HO representation. This chapter first spells out the general motivation for the HO view and the differences between HOP and HOT before considering key objections to the approach, as well as possible empirical support. Finally it looks at how the view addresses the explanatory gap and the hard problem of consciousness.

Explaining the “hard” problem

This chapter shows that global-workspace theory can be developed into a satisfying, fully reductive explanation of phenomenal consciousness. It shows how globally broadcast nonconceptual content enables higher-order thoughts about that content, where those thoughts can lack conceptual connections with physical, functional, or representational facts. As a result, zombies are conceivable and an (epistemic) explanatory gap is opened up. But the thoughts in question can themselves be given a fully naturalistic explanation. Hence all of the facts involved in consciousness can be fully explained. The chapter defends the reality of the phenomenal concepts needed to make this account work, and replies to a dilemma for the account proposed by David Chalmers.

Taking Apart the World

This chapter develops a characterization of the kind of reductive explanation that is the topic of the book. In particular, the book is concerned with substantive causal reductions rather than Nagel-style theory reductions. The characterization of reductive explanation that is developed here is based on Marie Kaiser’s account of explanatory reduction in biology, and, like Kaiser’s account, it highlights the importance of the fact that reductive explanations treat component systems as if they were parts in isolation. That is, in a reductive explanation it is assumed that our knowledge of how an element behaves in isolation can be useful in understanding the role that part plays when it is part of a complex system.

Introduction

This introductory chapter sets out the aim of this book: to investigate the metaphysical assumptions that underlie a pattern of ‘reductive explanation’ whereby we attempt to explain or predict the behaviour of a complex system by studying the system’s parts in isolation. It is argued that the success of reductive explanation is evidence for the truth of these metaphysical assumptions, and it is suggested that the ontology assumed by reduction can be put to use to shed light on the metaphysics of powers, causation, causal models, laws, emergence, and even normative ethics. This task is taken up in the remainder of the book.

Putting Things Together

This chapter brings together the discussions of the previous chapters in order to develop a model of reductive explanation that clarifies the role of causal powers and causal influences, and identifies a number of metaphysical assumptions made by the method of reductive explanation. These assumptions are metaphysical in the sense that they bear on issues of traditional concern to metaphysicians. In so far as the model presented here is an accurate account of how reductive explanation works, the great success of the reductive approach will be evidence for the truth of these presuppositions, and so will give us an empirical handle on various metaphysical questions. The presuppositions unearthed in this chapter will inform the metaphysical picture that is developed in subsequent chapters.

Causal Power

This chapter investigates the ontology of causal power and causal influence that was suggested by the discussion of reductive explanation in the previous two chapters. In particular, it is suggested that we should understand causal powers to be dispositions to manifest causal influence. Such powers, it is shown, can be given a conditional analysis that is less susceptible to counterexamples than conditional analyses of dispositions more generally. It is further argued that the conditional analysis can be extended to cover multi-track powers by using functions, rather than conditionals, to describe powers. Functional descriptions of powers connect nicely to the descriptions of force fields that one finds in physics, suggesting that we can interpret forces as influences in the sense described here.

Macroscopic Power and Influence

This chapter shows how causal powers and causal influences can be composed, both synchronically and asynchronically, to form composite powers and composite influences, which are a common feature of reductive explanation. Indeed, outside fundamental physics it is likely that many, if not all, the powers and influences mentioned will be composite rather than fundamental. A major part of this chapter involves defending the idea that composite influences can be composed of more basic component influences. In particular, it defends the idea from objections against the existence of composite and component forces. Since forces are paradigmatic examples of causal influence, these arguments will also be objections to the concept of composite influences more generally. Finally, having defended an account of the relation between composite and component powers, it show that this account defuses an argument recently advanced by Alexander Bird, who concludes that there are few, if any, true macroscopic powers.