Daniel Lemire's blog

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Science and Technology links (December 1st, 2017)

  1. Chollet has a piece on the impossibility of intelligence explosion. He is responding to the theory that smart machines will build even smarter machines, and that soon, human beings will become obsolete. He convincingly tears apart this theory. Human brains might be obsolete one day, but it is not as simple as setting up self-improving artificial intelligence in motion. He writes: we are our tools. He means that the model of intelligence as “brain in a jar” is hopelessly naive. I made much of the same points in a blog post published a week before Chollet’s essay: You are your tools. So to acquire more intelligence, we need to build more tools, and this takes time. Einstein would not have done so well on a deserted island. I do part company with Chollet when he writes:

Yet, modern scientific progress is measurably linear. I wrote about this phenomenon at length in a 2012 essay titled The Singularity is not coming. We didn’t make greater progress in physics over the 1950-2000 period than we did over 1900-1950, we did, arguably, about as well. Mathematics is not advancing significantly faster today than it did in 1920

What Chollet fails to appreciate, I fear, is the nature of progress itself. If we have chairs in 1750, it is not the case that chairs will get exponentially more confortable and cheaper over time so that a chair in 2017 should be expected to nourrish all your muscles for free. Bacteria that existed long before there were multicellular organisms are still around. If you go see a play today, it is not “exponentially better” than a play organized by Molière. Antibiotics are probably cheaper than they were in 1945, but they are not necessarily even better. Progress is about enabling new things. That’s how the exponential comes about: the number of new things you get grows and grows over time… at an exponential rate. Chollet is a great programmer who has produced software tools that are then used by lots of other engineers to build better tools, and so forth. What is being built is not just “better software”… it is software that solves problems we could not solve before. Just as one way of doing things becomes optimal, new alternatives open up. That’s called open-ended evolution and it is definitively happening.

  1. The sales of virtual-reality headsets have exceeded 1 million in the third quarter of this year. Half of these headsets are PlayStation VR headsets. If you achieve 1 million units per quarter, then you are at four million units per year. I have a bet with Greg Linden that we will soon achieve 10 million units a year. We are almost half-way there, so I think I still stand a chance of winning if there are interesting developments (like great games) in the near future.
  2. CRISPR/Cas9 is a technique to edit genes discovered in 2012. It is now relatively cheap and it is likely to be used in a few years to correct genetic defects. It works like a search and replace function. I wondered how fast it is:

it takes as long as six hours for Cas9 to search a bacterium, that is, through four million base pairs. (…) The results show that the price Cas9 pays for its flexibility is time, (…) To find the target faster, more Cas9 molecules searching for the same DNA sequence are needed. (…) Most proteins that search DNA code can recognize one specific sequence merely by sensing the outside of the DNA double helix, Cas9 can search for an arbitrary code, but to determine whether it is in the right place, the molecule has to open the double DNA helix and compare the sequence with the programmed code. The incredible thing is that it can still search the entire genome without using any energy.

I am no geneticist, but as a computer scientist, the thought that it takes an hour to process about a million base pair has me concerned. Human beings have 3 billion base-pairs per cell. Thankfully, the problem can be parallelized: you can use several Cas9 molecules.

  1. It looks like reducing the amount of iron in our brains could be useful in preventing cognitive decline. It is going to be re-tested in the context of Alzheimer’s. Much of our food has been supplemented from iron. Indeed, actual iron extracted from the ground is mixed with our food (e.g., bread, cereal). We tend to accumulate iron because the body has a hard time excreting iron. Though we need some iron to be healthy, too much iron in some tissues could be harmful.
  2. In Switzerland, a quarter of all clinical trials are never completed, according to a recent article. The article reviews all factors involved in such a high failure rate. Note that these are not mere failures to get scientific results… they are failures to even complete the scientific work. Some of the factors involved are intriguing. For example, if you want to run clinical trials in multiple cities, then you need ethics approvals in each city. Then there is the set of personal incentives which favor competition between researchers rather than broad collaboration.
  3. As men grow older, their testosterone levels fall and this leads, among other things, in muscle loss and sexual difficulties. Magnan observes that some men maintain high levels of testosterone well into old age. My instinct would be to go see these old men and find out how exactly they differ. Is there a genetic component involved?
  4. Kagan believes that we give pills too eagerly to school-age kids. He believes that labelling kids as having a deficit disorder, when their dopamine levels are perfectly fine, is bad for the kids. They are likely to internalize that there is something wrong with them. An interesting point he makes is that the increase number of prescriptions has a financial origin: insurance is likely to cover the cost, so it is free to the parents and to the school. I don’t know why we expect kids to sit at desks all day while listening to what an adult has to say. It does not sound like fun at all!
  5. According to Papadimitriou, many of us may not be getting enough vitamin D:

Since 2006, type 1 diabetes in Finland has plateaued and then decreased after the authorities’ decision to fortify dietary milk products with cholecalciferol. The role of vitamin D in innate and adaptive immunity is critical. A statistical error in the estimation of the recommended dietary allowance (RDA) for vitamin D was recently discovered; in a correct analysis of the data used by the Institute of Medicine, it was found that 8895 IU/d was needed for 97.5% of individuals to achieve values ≥50 nmol/L. Another study confirmed that 6201 IU/d was needed to achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L. The largest meta-analysis ever conducted of studies published between 1966 and 2013 showed that 25-hydroxyvitamin D levels <75 nmol/L may be too low for safety and associated with higher all-cause mortality (…)

  1. The ancient Greeks proved that the only regular polygons that tile are triangles, quadrilaterals and hexagons (as now seen on many a bathroom floor). My wife asked: “how did they prove it?” I don’t know how the Greeks proved it. I lazily looked up the answer online. Here is the gist of it. If you have a regular tiling, you can look at the vertices where different polygons meet, the sum of the angles must be 360 degrees. Then you can look at the inner angles formed by the regular polygons. Hexagons have inner angles of 120 degrees, so three hexagons can meet at a vertex, and their inner angles sum up to 360 degrees. Polygons with more sides have larger inner angles… approaching a flat 180 degrees. Suppose, for example, that two polygons with more than 6 sides meet up with a common vertex, then you sum up the two inner angles and what remains is smaller than the inner angle of the polygons and smaller than 180 degrees. With such arguments, you can construct a formal proof. But that’s not how the Ancient Greeks did it, surely?
  2. In a clinical trial, it was found that consuming twice the recommended amount of proteins improved muscle mass. This suggests that we should eat more proteins.
  3. Doctors trust male surgeons more.