Something wonderful happened around half a billion years ago and at least once. Feinberg and Mallatt take us through a very methodical and highly convincing argument that consciousness has its roots in vertebrate evolution and thus consciousness (as defined by American philosopher, Thomas Nagel as an experience of what it is like to be) is likely to be ubiquitously represented amongst all vertebrates we currently live alongside of. The conclusion that all vertebrates have always been conscious is not widely accepted by experts and seemingly not particularly palatable to a species that considers itself unique (and behaves accordingly) in the ability to think and consider its existence in the context of the world. Feinberg and Mallatt remind us that we are investigating a very basic consciousness but consciousness nevertheless. Some species understand their existence, that they are; others may muse on that in itself; and still fewer (perhaps just the one) consider that this is an interesting enough phenomenon to write a book about it. The Ancient Origins of Consciousness is a comprehensive update on the hard problem of consciousness. There are no prizes for guessing why philosopher David Chalmers named the task of objectively explaining the highly subjective nature of experience, The Hard Problem. This Hard Problem is of enormous interest to all who think, and its study has been traditionally the focus of philosophical investigation. As a hard problem, Feinberg and Mallet argue consciousness needs a multidisciplinary approach.

How does this physical thing mostly housed in our heads behind our eyes produce this phenomenal experience of consciousness and an understanding of what is like to be? The strapline How the Brain Created Experience hints that this study looks back at the evolutionary arrival of consciousness. On the dust jacket, Thurston Lacalli points out that hard problems need to be tackled at a base level, and in this case it seems sensible to ask what are the rudimentary forms of these phenomena as they emerge in evolution?

This study (and that is what it is—a serious study), The Ancient Origins of Consciousness approaches the hard problem from philosophical, neurobiological, and neuroevolutionary positions. The work is a result of the cross discipline collaboration of Todd Feinberg and Jon Mallatt. Feinberg is a neurologist, a practicting clinical psychiatrist (Icahn School of Medicine, NY) and the author of From Axons to Identity: Neurological Explorations of the Nature of the Self. Mallatt is an Evolutionary Biologist, Associate Professor of Biology and Medical Science (Washington State University and University of Washington).

Grounded by the basic philosophical puzzles of consciousness the authors go about very methodically investigating the structures of existing species and what we know of ancestral species using morphological (current and fossil), molecular and functional evidence. In this process, Feinberg and Mallatt ask very straightforward questions. What are the basic features that are needed for consciousness? When did these features first appear? Evidence strongly suggests that consciousness first appeared during the Cambrian explosion, when vertebrates first started to visually map their environments.

In a dedicated chapter, Feinberg and Mallatt raise the question, "Does consciousness need a backbone?" Posed in another way, could consciousness have evolved independently more than once? The authors note that invertebrates, despite having very different brain and sensory apparatus than vertebrates, have function consistent with consciousness. Octopuses, despite their apparent cleverness, are thought to fail crucial consciousness criteria with their independent neurally controlled arms. Countering this, The Ancient Origins of Consciousness makes a good case for mental unity in the octopus brain and therefore the possibilty of conciousness as defined as an experience of what it is to be. If this turns out to be the case, it is possible that consciousness have emerged in cephalpods ancestors alongside their post Cambrian evolution of good vision. Unfortunately, these species are not as well studied as vertebrates, and the authors remain cautious, judging cephalopod molluscs and arthropods as "probably conscious." If arthropds and cephalpods do turn out to possess conciousness, then without a doubt conciousness is considerably more widespread than is currently thought and has also emerged from the evolution of quite different neural structures. Independent evolution would help explain emerging evidence that other invertebrates may possess consciousness. Honey bees, for instance, have learning and memory abilities that appear to be able to comprehend certain abstract things. This seems incompatable with the size of their brains, which are very small but rather more dense than ours. In addition, the insect brain has neural aparatus similar to the vertebrate midbrain, backing up the idea that insects may as individuals have subjective awareness and at least a some sort of basic consciousness.

There it is. Consciousness predates us and not just us. Conciousness predates primates and mammals and possibly arose on more than one occasion. This is strong evidence that there exists a very significant survival advantage for any organism that is conciously aware of the risks and rewards of external environment, of its internal state, and has an experience of being, an awareness of self. Hence, it seems that we share a planet with conscious beings who experience what it is to be and understand themsleves as distinct from others. More study no doubt will shed more light on the extent of this, but consciousness it seems is quite possibly significantly more common than we might have believed.

While The Ancient Origins of Consciousness may require some commitment from the reader to navigate the multidiscipline approach necessary to address complexity of the hard problem, this well structured book is very much worth the effort required. As the authors stated in the preface "we do not skimp," and they certainly did not; but they have also designed this book thoughtfully to ensure that nonexperts can remain engaged and informed as they encounter very robust arguments and conclusions well supported on all fronts. From this perspective, no review can do justice to the work behind The Ancient Origins of Consciousness.