The Fabric of Reality

The Fabric of Reality, a 1997 book by David Deutsch, is full of great ideas, most of them surprising and intriguing. The main argument is that explanations are the centerpiece of science and that four theories play an essential role in our understanding of the world: quantum theory, the theory of evolution, the theory of computation and epistemology (the theory of knowledge).

You may raise a number of questions about these particular choices, such as why is the theory of relativity not there or why is the theory of evolution simply not a result of other theories in physics or even what makes epistemology to special. You will have to read the book to find out but the short answer is that not everything is physics and that theories at many levels are required to explain the world. Still, in physics, the most fundamental idea is quantum theory and it has profound impacts on our understanding of the universe. Perhaps the most significant impact comes from the fact that (according to Deutsch) what we know about quantum theory implies that we live in a multiverse. Each time a quantum phenomenon can conduct to more than one observable result, the universe splits into as many universes as the number of possible results, universes that exist simultaneously in the multiverse.

Although the scientific establishment views the multiverse theory with reservation, to say the least, to Deutsch, the multiverse is not just a theory, but the only possible explanation for what we know about quantum physics (he dismisses the Copenhagen interpretation as nonsense). Armed with these four theories, and the resulting conclusion that we live in a multiverse, Deutsch goes on to address thought-provoking questions, such as:

  • Is life a small thing at the scale of the universe or, on the contrary, is the most important thing on it?
  • Can we have free will, in a deterministic universe? And in the multiverse?
  • Do computers strictly more powerful than Turing machines exist, and how do they work?
  • Can mathematical proofs provide us with absolute certainties about specific mathematical statements?
  • Is time travel possible, at least in principle, either in the physical world or in a virtual reality simulator?
  • Will we (or our descendants, or some other species) eventually become gods, when we reach the Omega point?

The idea of the multiverse is required to answer most, if not all, of these questions. Deutsch is certainly not a parsimonious person when he uses universes to answer questions and to solve problems. The multiverse allows you to have free will, solves the paradoxes of time travel and makes quantum computers possible, among many other things. One example of the generous use of universes made by Deutsch is the following sentence:

When a quantum factorization engine is factorizing a 250-digit number, the number of interfering universes will be of the order of 10 to the 500. This staggeringly large number is the reason why Shor’s algorithm makes factorization tractable. I said that the algorithm requires only a few thousand arithmetic operations. I meant, of course, a few thousand operations in each universe that contributes to the answer. All those computations are performed in parallel, in different universes, and share their results through interference.

The fact that Deutsch’s arguments depend so heavily on the multiverse idea makes this book much more about the multiverse than about the other topics he addresses. After all, if the multiverse theory is wrong, many of Deutsch’s explanations collapse, interesting as they may be.

Still, the book is full of great ideas, makes for some interesting reading, and presents many interesting concepts, some of them further developed in other books by Deutsch, such as The Beginning of Infinity.


Enlightenment Now: The case for reason, science, humanism and progress

Steven Pinker’s latest book, Enlightenment Now, deserves high praise and careful attention, in a world where reason and science are being increasingly threatened. Bill Gates called it “My new favorite book of all time“, which may be somewhat of an exaggeration. Still, the book is, definitely, a must read, and should figure in the top 10 of any reader that believes that science plays an important role in the development of humanity.

Pinker’s main point is that the values of the Enlightenment, which he lists as reason, science, humanism, and progress have not only enabled humanity to evolve immensely since they were adopted, somewhere in the 18th century, but are also our best hope for the future. He argues that these values have not only improved our lives immensely, in the last two and a half centuries, but will also lead us to vastly improved lives in the future. “Dare to understand“, the cry for reason made by David Deutsch in his The Beginning of Infinity, is the key argument made by Pinker in this book. The critical use of reason leads to understanding and understanding leads to progress, unlike the beliefs in myths, religions, miracles, and signs from God(s).  Pinker’s demolition of all the values not based on the critical use of reason is complete and utterly convincing. Do not read this book if, at some level, you believe in things that cannot be explained by reason.

To be fair, a large part of the book is dedicated to showing that progress has, indeed, been remarkable, since the 18th century, when reason and science took hold and replaced myths and religions as the major references for the development of nations and societies. No less than 17 chapters are dedicated to describing the many ways humanity has progressed in the last two and a half centuries, in fields as diverse as health, democracy, wealth, peace and, yes, even sustainability.  Pinker may come up as an incorrigible optimist, describing a world so much better than that which existed in the past, so at odds with the most popular current views that everything is going to the dogs. However, the evidence he presents is compelling, well documented, and discussed at length. Counter-arguments against the idea that progress is true and unstoppable are analyzed in depth and disposed of with style and elegance.

But the book is not only about past progress. In fact, it is mostly about the importance of viewing the Enlightenment values as the only ones that will safeguard a future for humanity. If we want a future, we need to preserve them, in a world where fake news, false science, and radical politics are endangering progress, democracy, and human rights.

It is comforting to find a book that so powerfully defends science, reason, and humanistic values against the claims that only a return to the ways of the past will save humanity of certain doom. Definitely, a must read if you believe in, and care for, Humanity.

Our Final Invention: Artificial Intelligence and the end of the human era

In what regards the state of the art in Artificial Intelligence, and the speed that it will develop, James Barrat is extremely optimistic. The author of Our Final Invention is fully convinced that existing systems are much more advanced than we give them credit for, and also that  AI researchers will create Artificial General Intelligence (AGI) much sooner than we expect.

In what regards the consequences of AGI, however, Barrat is uncompromisingly pessimistic. He believes, and argues at length, that AGI will bring with it the demise of the human race and that we should stop messing with advanced AI altogether.

I found the arguments presented for both positions rather unconvincing. His argument for the most likely development of AGI in the next decade or so is based on rather high-level considerations and conversations with a number of scientists, researchers, and entrepreneurs from the field. Needless to say, they were picked from the ones most connected with his ideas. As for the arguments that AGI will be not only dangerous but, ultimately, fatal for humanity, they are borrowed, with minor changes, from the standard superintelligence (Bostrom) and intelligence explosion (I. J. Good) ideas.

From Watson’s performance in Jeopardy and from the ANN’s small victories in the perception fields, Barrat concludes, without any additional considerations, that AGI is around the corner and that it will be very, very, dangerous. The book was written before the recent successes achieved by DeepMind and others, which leads me to believe that, if written now, his conclusions would be even more drastic.

Even though there is relatively new material here, a few stories and descriptions are interesting. Barrat makes extensive use of his conversations with the likes of Omohundro, Yudkwosky, Vassar, and Kurzweil and some stories are very entertaining, even though they look a bit like science fiction. Altogether, the book makes for some interesting, if somewhat unconvincing, reading.

Mastering Starcraft

The researchers at DeepMind keep advancing the state of the art on the utilization of deep learning to master ever more complex games. After recently reporting a system that learns how to play a number of different and very complex board games, including Go and Chess, the company announced a system that is able to beat the best players in the world at a complex strategy game, Startcraft.

AlphaStar, the system designed to learn to play Starcraft, one of the most challenging Real-Time Strategy (RTS) games, by playing against other versions of itself, represents a significant advance in the application of machine learning. In Starcraft, a significant amount of information is hidden from the players, and each player has to balance short term and long term objectives, just like in the real world. Players have to master fast-paced battle techniques and, at the same time, develop their own armies and economies.

This result is important because it shows that deep reinforcement learning, which has already shown remarkable results in all sorts of board games,  can scale up to complex environments with multiple time scales and hidden information. It opens the way to the application of machine learning to real-world problems, until now deemed to difficult to be tackled by machine learning.

Virtually Human: the promise of digital immortality

Martine Rothblatt’s latest book, Virtually Human, the promise – and the peril – of digital immortality, recommended by none less than the likes of Craig Venter and Ray Kurzweil, is based on an interesting premise, which looks quite reasonable in principle.

Each one of us leaves behind such a large digital trace that it could be used, at least in principle, to teach a machine to behave like the person that generated the trace. In fact, if you put together all the pictures, videos, emails and messages that you generate in a lifetime, together with additional information like GPS coordinates, phone conversations, and social network info, there should be enough information for the right software to learn to behave just like you.

Rothblatt imagines that all this information will be stored in what she calls a mindfile and that such a mindfile could be used by software (mindware) to create mindclones, software systems that would think, behave and act like the original human that was used to create the mindfile. Other systems, similar to these, but not based on a copy of a human original, are called bemans, and raise similar questions. Would such systems have rights and responsibilities, just like humans? Rothblatt argues forcefully that society will have to recognize them as persons, sooner or later. Otherwise, we would assist to a return to situations that modern societies have already abandoned, like slavery, and other practices that disrespect basic human rights (in this case, mindclone and beman’s rights).

Most of the book is dedicated to the analysis of the social, ethical, and economic consequences of an environment where humans live with mindclones and bemans. This analysis is entertaining and comprehensive, ranging from subjects as diverse as the economy, human relations, families, psychology, and even religion.  If one assumes the technology to create mindclones will happen, thinking about the consequences of such a technology is interesting and entertaining.

However, the book falls short in that it does not provide any convincing evidence that the technology will come to exist, in any form similar to the one that is assumed so easily by the author. We do not know how to create mindware that could interpret a mindfile and use it to create a conscious, sentient, self-aware system that is indistinguishable, in its behavior, from the original. Nor are we likely to find out soon how such a mindware could be designed. And yet, Rothblatt seems to think that such a technology is just around the corner, maybe just a few decades away. All in all, it sounds more like (poor) science fiction than the shape of things to come.

Deepmind presents Artificial General Intelligence for board games

In a paper recently published in the journal Science, researchers from DeepMind describe Alpha Zero, a system that mastered three very complex games, Go, chess, and shogi, using only self-play and reinforcement learning. What is different in this system (a preliminary version was previously referred in this blog), when compared with previous ones, like AlphaGo Zero, is that the same learning architecture and hyperparameters were used to learn different games, without any specific customization for each different game.
Historically, the best programs for each game were heavily customized to use and exploit specific characteristics of that game. AlphaGo Zero, the most impressive previous result, used the spatial symmetries of Go and a number of other specific optimizations. Special purpose chess program like Stockfish took years to develop, use enormous amounts of field-specific knowledge and can, therefore, only play one specific game.
Alpha Zero is the closest thing to a general purpose board game player ever designed. Alpha Zero uses a deep neural network to estimate move probabilities and position values. It performs the search using a Monte Carlo tree search algorithm, which is general-purpose and not specifically tuned to any particular game. Overall, Alpha Zero gets as close as ever to the dream of artificial general intelligence, in this particular domain. As the authors say, in the conclusions, “These results bring us a step closer to fulfilling a longstanding ambition of Artificial Intelligence: a general game-playing system that can master any game.
While mastering these ancient games, AlphaZero also teaches us a few things we didn’t know about the games. For instance, that, in chess, white has a strong upper hand when playing the Ruy Lopez opening, or when playing against the French and Caro-Kann defenses. Sicilian defense, on the other hand, gives black much better chances. At least, that is what the function learned by the deep neural network obtains…
Actualization: The NY Times just published an interesting piece on this topic, with some additional information.

The Beginning of Infinity

David Deutsch‘s newest book, The Beginning of Infinity is a tour de force argument for the power of science to transform the world. Deutsch’s main point is that human intelligence, once it reached the point where it started to be used to construct predictive explanations about the behavior of nature, became universal. Here, “universal” means that is can be used to understand any phenomenon and that this understanding leads to the creation of new technologies, which will be used to spread human intelligence throughout the known universe.

The Beginning of Infinity is not just one more book about science and how science is transforming our world. It is an all-encompassing analysis of the way human intelligence and human societies can develop or stagnate, by adopting or refusing to adopt the stance of looking for understandable explanations. Deutsch calls “static” those societies that refuse to look for new, non-supernatural explanations and “dynamic” those that are constantly looking for new explanations, based on objective and checkable evidence. Dynamic societies, he argues, develop and propagate rational memes, while static societies hold on to non-rational memes.

In the process, Deutsch talks authoritatively about evolution, the universality of computation, quantum mechanics, the multiverse and the paradoxes of infinity. They are not disparate subjects since they all become part of one single story on how humanity managed to understand and control the physical world.

Deutsch is at his best when arguing that science and technology are not only positive forces but that they are the only way to ensure the survival of Humanity in the long run. He argues, convincingly, against the myth of Gaia, the idea that the planet is a living being providing us with a generous and forgiving environment as well as against the related, almost universal, concern that technological developments are destroying the planet. This is nonsense, he argues. The future survival of Humanity and the hope of spreading human intelligence throughout the Cosmos reside entirely in our ability to control nature and to bend it to our will. Otherwise, we will follow the path of the many species that became extinct, for not being able to control the natural or unnatural phenomena that led to their extinction.

Definitely, the book to read if you care about the Future of Humanity.