einstein

Albert Einstein and random thoughts on Machine Learning

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I read Einstein’s biography with as much enthusiasm as I did with Stephen Hawking’s A brief history of Time and Domigos’ The Master Algorithm. It’s not only because the book is recommended by, among others, Elon Musk, but probably more because of my childhood dream of becoming a physicist back when I was in high school. Although I was too dumb for physics, nothing could prevent me from admiring its beauty.

The book was excellent. Walter Isaacson did a great job in depicting Albert Einstein from his complicated personality to his belief, religion, politics, and, of course, his scientific achievements.

As a human being, Einstein is a typical introvert. He was always a loner, enjoyed discussing ideas more than any personal or emotional entanglements. During the most difficult periods of life, he would rather immerse into science rather than get up and do anything about his real-life struggles. To quote Isaacson, “the stubborn patience that Einstein displayed when dealing with scientific problems was equaled by his impatience when dealing with personal entanglements”, those that put “emotional burdens” on him. Some may criticise and regard him as being “cold-hearted”, but perhaps for him, it was way easier to use the analytical brain rather than the emotional brain to deal with daily mundane affairs. This, often times, resulted in what we can consider as brutal acts, like when he gave Mileva Maric a list of harsh terms in order to stay with him, or when he did almost nothing for his first kid, and let it die in Serbia. For this aspect, though, he probably deserves more sympathy than condemnation. He was surely a complicated man, and expecting him to be well-rounded in handling personal affairs is perhaps as unreasonable as impossible.

Now, it is perhaps worth emphasizing that Einstein is a one-in-a-million genius who happens to have those personality traits. It does not imply those who have those traits are genius. Correlation does not imply causation 😉

Einstein made his mark in physics back in 1905 when he challenged Newton’s classical physics. He was bold and stubborn in challenging long-standing beliefs in science that are not backed by any experimental results. Unfortunately during his 40s, quantum physics made the same rationale, and he just couldn’t take it, although he contributed a great amount of results in its development (to this he amusingly commented: a good joke should not be repeated too often). His quest to look for a unified field theory that can explain both gravitational field and electromagnetic field by a consise set of rule was failed, and eventually quantum mechanics, with a probabilistic approach, was widely accepted. This saga tells us a lot:

  • The argument Einstein had with the rest of physicists back in 1910s on his breakthrough in relativity theory was almost exactly the same with the argument Neils Bohr had in 1930s on quantum theory, except that in 1930s, Einstein was on the conservative side. In 1910s, people believed time is absolute, Einstein shown that was wrong. In 1930s, Neils Bohr used probabilistic models to describe subatomic world, while Einstein resisted, because he didn’t believe Nature was “playing dice”.
    Perhaps amusingly, one can draw some analogies in Machine Learning. Einstein’s quest to describe physics in a set of rules sounds like Machine Learners trying to build rule-based systems back in 1980s. That effort failed and probabilistic models took advantages until today. The world is perhaps too complicated to be captured in a deterministic systems, while looking at it from a different angle, probability provides a neat mathematical framework to describe uncertainties that Nature seems to carry. While it seems impossible to describe any complicated system deterministically, it is perhaps okay to describe them probabilistically, although it might not explain how the system was created in the first place.
  • During the 1930s, in a series of lonely, depressing attempts to unify field theories, Einstein sounds a lot like… Geoff Hinton who attempted to explain how the human brain works. Actually, those are perhaps not too far from each other. The brain is eventually the 3-pound universe of mankind, and completely understanding the brain is probably as hard as understanding the universe.
  • Being a theorist his whole life, Einstein’s approach to physics is quite remarkable. He never started from experimental results, but often drawn insights at the abstract level, then proceed with intuitive thought experiments, and then went on with rigorous mathematical frameworks. He would often end his papers with a series of experimental studies that could be used to confirm his theory. This top-down approach is very appealing and became widely adopted in physics for quite a long time.
    On the contrary, many researches in Machine Learning are often bottom-up. Even the master algorithm proposed in Domigos’ book is too bottom-up to be useful. Computer Science, after all, is an applied science in which empirical results are often too emphasized. In particular, Machine Learning research are heavily based on experiments, and theories that justify those experiments often came long after, if there was any. To be fair, there are some work that come from rigorous mathematical inference, like LSTM, SELU and similar ideas, but a lot of breakthroughs in the field are empirical, like Convolutional nets, GANs and so on.
    Looking forward, drawing insights from Neuroscience is probably a promising way of designing Machine Learning systems in a top-down fashion. After all, human brain is the only instance of general intelligence that we known of by far, and the distribution of those generally intelligent devices might be highly skewed and sparse, hence drawing insights from Neuroscience is perhaps our best hope.
  • The way Einstein became an international celebrity was quite bizarre. He officially became celebrity after he paid visits to America for a series of fund-raising events for a Zionist cause in Israel. The world at the time was heavily divided after World War I, and the media was desperately looking for a international symbol to heal the wounds. Einstein, with his self-awareness, twinkling eyes and a good sense of humour, was too ready to become one. American media is surely good in this business, and the rest became history.
  • Einstein’s quest of understanding universe bears a lot of similarities with Machine Learner’s quest of building general AI systems. However, while computer scientists are meddling with our tiny superficial simulations on computers, physicists are looking for ways to understand the universe. Putting our work along side physicists’, we should probably feel humbled and perhaps a bit embarrassing.

It was amazing and refreshing to revise Einstein’s scientific journey about 100 years ago, and with a bit of creativity, one could draw many lessons that are still relevant to the research community today. Not only that, the book gives a well-informed picture about Einstein as a human, with all flaws and weaknesses. Those flaws do not undermine his genius, but on the contrary, make us readers respect him even more. Therefore Einstein is, among others, an exemplar for how much an introvert can contribute to the humankind.

For those of us who happen to live in Berlin, any time you sit in Einstein Kaffee and sip a cup of delighting coffee, perhaps you could pay some thoughts to the man who lived a well-lived life, achieved so much and also missed so much (although the Kaffe itself has nothing to do with Einstein). Berlin, after all, is where Einstein spent 17 years of his life. It is where he produced the general relativity theory – the most important work in his career, it is the only city he considered to be home throughout his bohemian life.