In his Prologue, Antti Revonsuo describes the main task of his book: “To depict a biological research program on consciousness.” (pg. xviii). He is interested in drawing upon proven research strategies to describe how we can study consciousness from a biological perspective that would allow us to ultimately answer the question: “What the place of the subjective psychological reality is in the physical universe?” (pg. xvi). In short, why has consciousness as a biological reality emerged to aid the process of evolution?

He comments: “I fear that the problem of consciousness will never be resolved all of a sudden by constructing a single philosophical argument, no matter how witty, nor by running a single brain imaging experiment, no matter how ingenious. Instead of such isolated attempts, an overall scientific research program is needed that provides a general philosophical and empirical framework, the big picture, to which the problem of consciousness can be firmly anchored, and consequently, taken apart bit by bit and thereby solved, step by step. After all, that is how biological science has succeeded in solving other great mysteries of nature which once seemed eternal and irreconcilable.” (pg. xviii). Revonsuo's book: Inner Presence: Consciousness as a Biological Phenomenon attempts to do just that. He argues that science can explain consciousness if it goes about this task in a systematic manner. It must begin with the philosophical assumption that consciousness is real and is a biological phenomenon. From a philosophical perspective, he therefore argues for biological realism as the basis for studying consciousness.

Next, he argues that the explanation of consciousness requires a unified research program. Fragmented research studies which are not a part of a research program, he suggests, frequently are a “dead-end.” The research program must be based on clearly articulated assumptions about how to approach the task. One assumption is that an explanation in the biological sciences is fundamentally different than an explanation in physics. The second assumption is that biological explanations require a multilevel explanation model. He notes that in biology the “multilevel explanation” is the rule for explaining complicated phenomena. He emphasizes that biological phenomena must be studied at different levels of organization. Only when these different levels of organization can be integrated does true understanding of the phenomena emerge. A clear strength of his book and of his approach is reflected in Figure 1.8 (reproduced here). It outlines his approach to the scientific study of consciousness which has considerable merit.

Reproduced with permission from MIT Press (Inner Presence: Consciousness as a Biological Phenomenon, by Antti Revonsuo, 2006, p. 26, Fig. 1.8).

Studies dealing with human consciousness must approach the problem from at least three different perspectives. One perspective is to understand what brain structures and physiological events are involved in producing consciousness at different stages of human development. This is the “backward-looking explanation.” The study of consciousness also requires a thorough analysis of the biological subcomponents that make consciousness possible in the “here and now.” This would include an analysis of how different brain regions interact with one another via neurotransmitter events and emerging physiological properties that make a phenomenological experience possible. This is the “downward-looking explanation.” Finally, the scientific study of consciousness must also approach the question of what is the role of consciousness for overall brain function. How does it facilitate, for example, learning and memory? How does it influence the development of language? How does it help the organism deal with the environment more effectively? This is the “upward-looking explanation,” and ultimately attempts to answer the very broad but important question of the role of consciousness in a physical universe.

This book would be worth reading just on the basis of these few ideas, but in fact, it presents many more interesting concepts. The author reviews, for example, how the biology of visual perception and its various disorders, the technology behind virtual reality, and present-day neuroscience studies on consciousness may help provide insights as to how to approach the problem of consciousness at the different levels that were outlined in Figure 1.8. However, the most intriguing part of this book is the author's suggestion that scientific studies of dreams may provide a means for understanding how subjective experiences emerge in the non-sleep state. Revonsuo emphasizes that “discovering consciousness in the brain will require that we are capable of constructing a multilevel theoretical model of the phenomenological level and its mechanisms.” (pg. 298). He notes that it is in precisely the state of dreaming that there is a phenomenological state that potentially could be studied from the multilevel model that he proposed in Figure 1.8. One could ask the question: what are the brain events that make dreaming possible? What is the purpose of dreaming? What are the micro-level mechanisms responsible for the phenomenological experience of a dream? This is a fascinating approach to the problem of consciousness. He states, if we could develop a “dream catcher test” (pg. 300), we could then make a quantum leap in understanding the biology of subjective phenomenological experience. His explanation of how this can actually be done is somewhat laborious and at times difficult to follow, but basically he has this to say.

Imagine that we have a “brain team” and a “dream team.” The brain team would collect data in the laboratory. It would study the neuroanatomical, neurophysiological, and neurochemical substrates of dream images. A dream team would also exist that could quantify what the actual subjective images were in the context of any given dream and how they interact. He then goes on to suggest that “the task for both teams is to construct, from the different sources of data available for each team, a full-scale, multimodality, 3D computer animation of the dream events that unfolded just prior to awakening the subject, and exactly as they were experienced by the subject. Both teams work independently, without knowing anything about each other's work. The resulting dream models will portray—in as much detail as possible, and as closely resembling the subject's original experience as possible—the dream setting, the objects, persons, and interactions present in the dream; and the temporal progression of the dream events” (pg. 302). In other words, by taking the knowledge that emanates from the neurosciences and biology and combining it with knowledge that would come from the psychological description of a person's dream, one could bring these two bodies of information together and integrate different levels of knowledge. This would allow us to predict, from a biological perspective, what is experienced as a phenomenological state during dreaming in a given subject. While this is a fascinating idea, it is one that still remains difficult to imagine as to exactly how this would be done. Moreover, the relevance of specific dream images for a given individual with a unique psychosocial history is not adequately considered by Revonsuo. For example, one person may dream being on a large ocean liner that has no side rails, but is moving slowly out to the open sea. It may stimulate in that individual a sense of excitement and wonder regarding the future. For another individual, the same visual images might produce anxiety and worry about falling off of the ocean liner into the sea. The same mental/visual image of an ocean liner without side rails moving into the open sea could carry with it completely different psychodynamic meanings and affective experiences. This is not adequately considered when attempting to apply the “dream catcher test” to the study of consciousness. It is, from the point of view of this reviewer, the major weakness of Revonsuo's innovative approach.

Nevertheless, the strength of this book is in helping us “think outside of the box” and seriously consider developing a research program that encourages scientists to coordinate their efforts to approach the study of human subjective experience (i.e., consciousness) from multiple levels, which have as their goal convergent information which leads to predictive validity. Anyone interested in the problem of impaired self-awareness after brain injury will enjoy reading Revonsuo's Inner Presence: Consciousness as a Biological Phenomenon.