David Deutsch's excellent (2011) book: The Beginning of Infinity has been a major influence on my recent work in the field of dysology. Deutsch's clear writing helped me to see more clearly how the philosophy of science allows us to know what makes an explanation good or bad. I used his book as a framework to criticise the current notion of so called 'crime science' that is being propagated within the Jill Dando Institute for Security and Crime Science at the University College London. Deutsch's explanation of Karl Popper's philosophy made clear for me several things that I already knew before reading it. What Deutsch did was to enable me to understand those ideas better, and to appreciate the magnitude of their importance in helping us tell good explanations from bad. Deutsch is an expert universal explainer of existing knowledge and adds to what we know with more than a few new and important explanations of his own. For example, he has reversed my opinion regarding the hypothesis (that has become orthodoxy) that underpins Jared Diamond's award winning book Guns Germs and Steel. If you are seriously interested in knowing what makes a good or bad explanation for anything then I suggest you buy Deutsch's book today. I bought mine from Amazon and saved money since it is retailing at my local book shop in Nottingham England for £25. So far so good then because in many areas Deutsch meets the test set by the great mathematician David Hilbert who said at the second International Congress of Mathematicians in Paris in the summer of 1900: "An old French mathematician said: `A mathematical theory is not to be considered complete until you have made it so clear that you can explain it to the first man whom you meet on the street.' This clearness and ease of comprehension, here insisted on for a mathematical theory, I should still more demand for a mathematical problem if it is to be perfect; for what is clear and easily comprehended attracts, the complicated repels us." (David Hilbert 1900). Deutsch's Dog's Dilemma Personally, I struggled with the explanation of infinity in this book regarding a thought experiment in a hotel with an infinite number of rooms. In the explanation a dog that is moved from room to room ceases - at some point - to exist. The dog is (or becomes) nowhere. That explanation was lost on me and seems to contradict later quantum mechanics arguments in the book that I understand are claiming that things will always exist once they have existed. But then I'm no quantum physicist. I'd like to know more about that dog and why it is no more and nowhere, just in case I end up interfering with photons and atoms in the multiverse to influence a distant - or very close - world where just such a hotel exists and where I am a dog being passed from room to room. Should I bite someone in the hotel, perhaps a version of David Deutsch, before it's too late? Would that act save me from non-existence and if so at what point must I bite before it's too late? If I do bite one of those hotel guests, making them drop me before they can pass me on, in what direction should I run so as not to cease to exist? If I run along the corridor in the same direction and at the same rate as I was being passed from room to room by the guests would I still cease to exist at some point? Would I never find my way out of the corridor of Infinity Hotel, and if so should I keep shifting my running directions so as not to cease to exist? Would the safest option be to remain static and chase my tail for amusement and exercise? But if that is the safest option then what is the difference between dogs existing in Infinity Hotel and human civilizations ceasing to exist due to their static thinking? In short, please tell me more about the poor darn dog so that the written explanation for the theory makes more sense and so that I can try to square it with other knowledge in this book about successful and unsuccessful societies. Let me explain further what I meant by that last sentence and why the question about the dog troubles me. Deutsch makes a compellingly rational argument that good ideas have infinite reach. He goes on to make a brilliant contribution - through the clarity of his explanation of Richard Dawkins' theory and his own ideas on the subject - to our understanding of memes. To digress, it was this part of his book that sparked my own idea, as a criminologist, that perhaps crime is the ultimately selfish meme. For those unfamiliar with the concept, memes are ideas that survive in human culture in the same way as genes in do in living matter by selfishly passing themselves on. The Christian religion, for example, is a meme. Ok back to my confusion, so what I can't understand from reading Deutsch's written explanation of infinity is what would happen in David Hilbert's Grand Infinity Hotel (see: Olein 2001 for the story behind Infinity Hotel) if it was an idea (a meme) that was so complicated it had to be written down was passed along from room to room rather than a dog? If that idea was a good explanation for infinity, according to Deutsch's explanation it could not have infinite reach because at some point along the infinite corridor of knowledge in Infinity Hotel the brilliant but complex idea would cease to exist. In that case how would it still have the capacity for infinite reach if it ceased to exist somewhere further along the infinite corridor of knowledge as a singularity? Infinity Hotel, which can always accommodate more infinitely countable guests even when it is full but it cannot accommodate good explanations that are so complex they have to be written down to be passed on as memes. This leads me to ask the following question: Does the fact that good physically recorded explanations, just like other physical objects such as dogs, do not have a fundamental place and are not unlimited in their scope and power within the brilliant mathematical world of Hilbert's Grand Infinity Hotel have any significance for Deutsch's massive paradigm shifting claim that 'explanations' have a fundamental place in the universe? I am not so self-deluded as to suppose that the above questions pose any kind of paradox that Deutsch will now have to deal with. Rather, I suspect I've made some kind of naive mistake in asking these questions - perhaps something close to Zeno's mistake (which Deutsch explains well). But that is my point, the book is written as much for non-quantum physicists as it is for them. Indeed, all the explanations are written in text, which is good because I hate equations and can't make head nor tail of most of them. But that leaves me with this Dog Dilemma, so that I'm now, in my ignorance as a social scientist, left awake at night to wonder whether there is a dog. Infinity Hotel is obviously an analogy, but unless the analogy can tell us more about these obvious 'what happens if and why' questions about Deutsch's dog then as Deutsch himself teaches us in this book: "Arguments by analogy are fallacies. Almost any analogy between any two things contains some grain of truth, but one cannot tell what that is until one has an independent explanation for what is analogous to what and why." (p.371) As far as vanishing dogs and annihilated memes go in Infinity Hotel, I'm not sure Deutsch does make such complexities explainable to the person in the street. Another criticism that I do have is that when he first begins to write about abstractions Deutsch assumes the reader knows both what an abstraction is and what type of abstraction he is thinking of. Once you read Deutsch's remarkable book, those past few paragraphs might not read anything like as crazy as you may think they are. If you can think then I think that this book should change the way you think about thinking forever. I did find the imagined ancient Greece philosopher's dream chapter very boring and so I skipped it because it seemed to have nothing new to add to what Deutsch had already explained in his careful and elegant explanatory prose. But that's it for personal negative criticisms and my personal confusion. Because overall, this is - as so many others are saying - going to be a classic book. But wait. No! That's a prophecy and not a scientific prediction. So, I'm being irrational now and I could easily be very wrong. Why? Well, you'll have to read the book to find out. I would willingly place a large wager on Professor David Deutsch - with this remarkable explanatory text - going on to inspire and guide an infinity of future thinking and knowledge progression. Deutsch is today the man to beat as the world's greatest living universal explainer. One day I would like to know his thoughts on Lovelock's Gaia Theory and on the whole notion of self-regulating complex systems - be they physical or social. Besides the Kindle edition, I bought my hard copy of this book only three weeks ago and it's a first edition. Do you know what a first edition of Darwin's Origin of Species fetches today? I feel like going out and snapping up another 100 of the printed version for my pension fund. Reference Hilbert, D. (1900) Mathematical Problems. Lecture delivered before the International Congress of Mathematicians at Paris in 1900. [...] Olein, R. (2001) Hilbert's Problems. Mission College. Final Paper - Math G S01 [...] Dr Mike Sutton is author of Nullius in Verba: Darwin's greatest secret