The Emperor’s New Mind contrasts two theories of mind, that of strong AI and an alternative being somewhat tentatively put forward by Prof. Penrose. The focus of the book is on consciousness. With respect to minds, there are many different perspectives, such as that of free will, and the “mind-body” problem, in the context of Descartes’ philosophy, but Prof. Penrose prefers to confine his discussion to viewpoints of greatest relevance to the nature of consciousness. He views strong AI as the claim that computers can simulate minds, and that sufficiently well-designed and complex computers will display consciousness. He reduces this to the claim that consciousness arises out of algorithmic structures and processes that are sufficiently complex, but feasibly within the possibilities for real computers. His view, contrary to this, is that consciousness is not algorithmic: Computers, at least as they exist now, cannot become conscious, as we humans are. His thesis is two-pronged: One is that a successful theory of mind will depend on the extension of physical theory as we now know it. He illustrates this by showing that a successful theory of quantum gravity might explain consciousness. The other part of his approach depends on Godel’s theorem. As this is a metamathematical result, and its truth recognized outside the bounds of logical and mathematical algorithms, he asserts that this means there are truths we have access to as conscious beings that a computer could not. An extremely important support for this comes from his beliefs as a Platonist. We manifestly have access to an ideal realm where truth can be grasped outside of the structure and processes involved with algorithms. We have direct access to certain truths. It is important to point out that Platonism is almost a requirement for an appreciation of the validity of Godel’s results. Godel himself was a Platonist. A further point is that Platonism gives a great deal of guidance with respect to physics. Prof. Penrose is a mathematician with profound geometric insights, and combining this with Platonism yields powerful arguments that he can adduce about physics. Thus, in a sense, his book is contrasting an Aristotelian perspective, namely that of strong AI, with his brilliant insights derived in part from his Platonic philosophy. A question that arises is how seriously he presents strong AI as an alternative to his point of view: Is it just a straw man? This involves a subjective judgement on the part of the reader. I felt that overall, despite his biases as a result of his beliefs, that he displays a remarkable sharpness of intellect, as well as open mindedness. He is clearly biased toward his point of view, but he also does not treat strong AI as merely a straw man. Considering that he believes an advance in basic physics is necessary to understand consciousness, he must connect our biological knowledge of the brain with quantum gravity. This is a rather difficult connection, to say the least, and it requires an extensive discussion of modern physics to establish a suitable framework for understanding his perspective. He takes us on a splendid tour, extremely exhilarating, of certain important areas of modern physics. His geometric perspective is extremely interesting, and we get a powerful vision of a number of areas of physics that I found to be enlightening, despite the fact that my background in physics is fairly substantial. He keeps his discussion, for the most part, at a level of about a junior physics major in college. Sometimes more extensive knowledge is quite a bit of help. And, because his writing is very clear, an indicator of how important he evidently felt these matters were, even people not trained in physics will be able to derive much from the discussion, although they will not comprehend certain subtleties. This treatment of modern physics is a classic presentation, and certainly makes the book worth reading, even if one finds Prof. Penrose’s ideas about a theory of mind somewhat too speculative. Because so much depends on Godel’s famous work, he also discusses this in depth. In conjunction with this, he provides a good discussion of Turing machines. Overall, I think that this book must be highly recommended. It gives some excellent insights into Prof. Penrose’s perspectives and geometric thinking. Since he is (or was) quite a brilliant mathematician, this insight is a very welcome view into the thinking of one of the premier physicists of the latter part of the twentieth century. Also, the view he presents of modern physics is a treat, and done with remarkable clarity.