The author's goal is to answer the question as to whether a (non-human) machine can imagine. Clearly he believes that machines can, and throughout the book he gives his reasons for believing so. Early on, he emphasizes to the reader that he is an engineer, but given the view by most that engineering is a practical profession, he also wants the reader to know that it is philosophy that permits a true understanding of the nature of machine intelligence and forms the proper context for addressing questions regarding the ability of machines to have an imagination. Indeed, research into machine imagination is considered to be a combination of engineering and philosophy. Those readers, including this reviewer, who find philosophical speculation a distraction to the actual construction of intelligent machines might not want to read further. However, there is enough discussion on the history of the author's involvement in the development of intelligent machines to make the book worthwhile to read. This is especially true for the author's discussion on the MAGNUS machine, which he considers to be a machine "driven by inner states." In addition, the author is very aware of the pitfalls of philosophical musings on the nature of consciousness and machine intelligence. One of these concerns the conflict between the use of mathematics and physics to promote true understanding, versus the insistence that such understanding can only be reached from the use of thought experiments and argumentation. Another problem, says the author, is the predilection of philosophers to deny or negate the thoughts of their predecessors, which stymies progress to true understanding and is to be contrasted with the more effective approach in scientific circles, where consensus can be reached based on available evidence. Lastly, the author believes, the drive to understand consciousness has driven philosophers to the embrace of mysticism, with a consequent rejection of quantitative approaches.
The design of non-biological machines with imagination is not only driven by curiosity, but also by the desire to shed light on the nature of consciousness itself, says the author. The actual implementation of conscious imagination in non-biological machines can assist in the understanding of how it is done in biological machines, or at least how they are to be contrasted. The mechanisms giving rise to imaginative consciousness may have common elements in biological and non-biological machines. The author wants to find what aspects of "artificial" imagination are in fact true for "real" imagination.
At various places in the book, the author includes hypothetical discussions and debates with various philosophers and notable persons in history. These are interesting for sure, but they distract the reader from the discussion on the actual engineering of conscious and imaginative machines. Philosophers who find machine consciousness an elusive or impossible goal will never be convinced by any arguments supporting this goal. It would be better if researchers in machine intelligence would declare a moratorium on philosophical debate and speculation, and instead get busy with the real goal of designing and constructing intelligent machines.
The author characterizes consciousness in a machine as being the ability to know where it is situated, as being an understanding of its origins, and having its own motivations for the making of decisions. These criteria don't really that seem to difficult to implement in non-biological machines, and as one reads the book it becomes more apparent with each passing page that the author does not consider the implementation of non-biological machine consciousness as being a problem of overwhelming difficulty. His optimism in this regard is very characteristic of those who work in the field of machine intelligence. Their efforts are admirable, and even though the engineering of consciousness in a non-biological machine may remain elusive in years to come, there is no doubt that various types of machine intelligence have been realized in some of the machines of today. We can only expect further advances, and the rise of new types of intelligent machines. Whether these machines meet our expectations is another matter, but they have already exceeded expectations in many cases. Conscious or not, the machines of the future will certainly be fascinating entities with which to interact.