Francis Crick (1916-2004) was a British molecular biologist, physicist, and neuroscientist, who was jointly awarded the 1962 Nobel Prize for Physiology or Medicine as one of the co-discoverers of the structure of the DNA molecule in 1953. In later years, Crick had been exploring more "philosophical" areas of science (see his books such as Life Itself: Its Origin and Nature and What Mad Pursuit: A Personal View of Scientific Discovery, as well as the present book). [NOTE: page numbers below refer to the 319-page 1094 hardcover edition.]
He wrote in the Preface to this 1994 book, "This book is about the mystery of consciousness---how to explain it in scientific terms. I do not suggest a crisp solution to the problem. I wish I could, but at the present time this seems far too difficult... What I have tried to do here is to sketch the general nature of consciousness and to make some tentative suggestions about how to study it experimentally... What I want to know is exactly what is going on in my brain when I see something... The message of the book is that now is the time to think scientifically about consciousness (and its relation, if any, to the hypothetical immortal soul) and, most important of all, the time to start the EXPERIMENTAL study of consciousness in a serious and deliberate way." (Pg. xi-xii)
He begins with the statement, "The Astonishing Hypothesis is that 'You,' your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules... This hypothesis is so alien to the ideas of most people alive today that it can truly be called astonishing." (Pg. 3) He admits that some people "are called 'dualists'---they believe matter is one thing and mind is something completely different. Our Astonishing Hypothesis says, on the contrary... that it's all done by nerve cells. What we are considering is how to decide between these two views experientially." (Pg. 33)
Much later, he admits, "there is no lack of plausible ideas and feasible experiments. What is disappointing is that, at the moment of writing, there does not appear to be one set of ideas that click together in a convincing way to make a detailed neural hypothesis that has the smell of being correct. If you think I appear to be groping my way through the jungle you are quite right." (Pg. 250-251) He asserts, "I believe that when the neural basis of consciousness is thoroughly understood this knowledge will suggest answers to two major questions: What is the GENERAL nature of consciousness, so that we can talk sensibly about the nature of conscious in other animals, and also in man-made machines, such as computers? What advantage does consciousness give an organism, so that we can see why it has evolved?... What may prove difficult or impossible to establish is the details of the subjective nature of consciousness... This symbolism may be impossible to convey to another organism in a direct manner until and unless we can hook two brains together ... But without understanding the neural correlates of consciousness I do not believe that any of these questions can be answered in a manner that all thoughtful people would accept." (Pg. 252)
He asks, "Will we be able... to build such machines and, if we did, would they appear to possess consciousness? I believe that in the long run this may be possible, although there may turn out to be technical limitations that are almost impossible to overcome. In the near future I suspect that any machines we can construct are likely to be very simple in their capabilities compared to the human brain. Because of this they will probably appear to have only a very limited form of consciousness... like the brain of a frog or even that of a humble fruit fly." (Pg. 257)
He proposes a concept of Free Will: "My first assumption was that part of one's brain is concerned with making plans for future actions... My second assumption was that one is not conscious of the 'computations' done by this part of the brain but only of the 'decisions' it makes... My third assumption was that ... one has immediate recall of what is decided but not of the computations that went into the decision... such a machine... will appear to itself to have Free Will ... Such a machine can attempt to explain to itself why it made a certain choice (by using introspection). Sometimes it may reach the correct conclusion. At other times it will either not know or, more likely... has no conscious knowledge of the 'reason' for the choice." (Pg. 266)
He concludes, "It is important to emphasize that the Astonishing Hypothesis is a hypothesis. What we already know is certainly enough to make it plausible, but it is not enough to make it as certain as science has done for many new ideas about the nature of the world." (Pg. 257) He adds, "If the scientific facts... support the Astonishing Hypothesis, then it will be possible to argue that the idea that man has a disembodied soul is as unnecessary as the old idea that there was a Life Force... It would be comforting to believe that most people would be so convinced by the experimental evidence that they would immediately change their views. Unfortunately, history suggests otherwise." (Pg. 261)
This is a very thought-provoking book, whether or not one agrees with all (or even any!) aspects it, and it will be of considerable interest to students of cognitive neuroscience, philosophy of mind, artificial intelligence, etc.