“Physics Needs Philosophy” Says Rovelli

Dr. Carlo Rovelli, a famous founding father of Loop Quantum Gravity Theory, has written an interesting essay with the thesis that physicists need to pay attention to philosophy rather than disparage or dismiss it. The essay was published online by Springer last month. You can read or download the PDF here: Physics Needs Philosophy_Rovelli

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deFacebooked

The purpose of this brief post is merely to announce that I am no longer on Facebook.

I did not use it that much anyway, except to have my tweets posted automatically to my wall. I log in about once a year to check my privacy settings and make sure everything looks alright. But today when I attempted my annual login, Facebook said my account had been locked. It said I could contact three “friends” for help, and gave me a list people I do not recognize. There was one alternative: to upload an official photo ID, such as a driver’s license. I would have to be a special kind of fool to give them my personal information.

Thus I shall not be posting on Facebook for the foreseeable future. If you see anyone posting under the name Ander Nesser, that is not me. It’s okay, though. I would rather be bookfaced.

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“Generation upon Generation” and “The Long Childhood”

Welcome to the twelfth episode of Electric Chapter Lab. Today we shall complete our review of The Ascent of Man.

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Generation upon Generation

In Chapter Twelve, Dr. Bronowski continues the story of Chapter Nine by discussing more aspects of biology: heredity, genetics, and cell biology.

Bronowski relates the story of Gregor Mendel, who predicted and confirmed that some traits in pea plants are not an average mix of parents, but transmitted as unmixed units. He then discusses the discovery of DNA and reviews the basics of cell biology. Most of the information in this chapter is middle school level–I do not mean that pejoratively, but honestly. My high school biology class covered more advanced material. I suspect that most readers of this blog would also be familiar with the concepts of this chapter, as we hear things about it almost every day, especially since the genomics revolution. Perhaps the general public was less familiar in 1969, when this book was written. So let us move on to the final chapter.

The Long Childhood

In Chapter Thirteen, the final chapter, Dr. Bronowski contemplates the importance of child-like qualities in humans and their civilizations.

Bronowski claims that justice is a cultural universal, and a biological aspect of Man. Maybe I am missing something in the text, but I cannot find where he explicitly explains this. I am not even sure of the claim being made, unless it is just the trivial one that every thought we have or action we perform is an aspect of biology in some sense, given that we are biological organisms.

At one point, Bronowski makes the claim that brains are not computers: “If the brain were a computer, then it would be carrying out a pre-wired set of actions in an inflexible sequence” and the brain is plastic; it learns: therefore it is not a computer. Bronowski must have in mind some specific type of computer that was around in the 1960s. But a computer is anything which processes information, so of course our brains are computers. And our brains are programmed from birth and earlier; there is a “pre-wired set of actions” in our genes and epigenes. It is fine for Bronowski to emphasize the unique plasticity of our minds–it is quite amazing, after all–but he is being too dismissive of our inherited core programming.

He goes on to describe the special talents of humans, which correspond to special learning areas in the brain: hand manipulation, speech, and predicting / planning. He also mentions, in reference to the chapter title, that humans are neotenous: we are still embryos when we are born, and we retain child-like traits in adulthood. In preparation for adulthood, we practice delayed gratification and delayed decision-making, which is unlike other animals. In failed cultures, children are restricted in imagination. They are forced to be the same as adults, so each generation is the same and the growth of knowledge stagnates. These cultures discourage the asking of questions.

This leads Bronowski into values and ethics, and he says something I wish to highlight:

“Knowledge is … a responsibility for the integrity of what we are … as ethical creatures. You cannot possibly maintain that informed integrity if you let other people run the world for you while you yourself continue to live out of a ragbag of morals that come from past beliefs.”

What is the meaning of a scientific society? Bronowski spends the last few pages contemplating that. His final thought is an uplifting one about human nature: Our imagination can lead to fear, but we counter that with commitment to our endeavors.

Overall Assessment

At several points over the course of this review, I have expressed frustration with a few of Bronowski’s misconceptions. However, that does not significantly reduce the achievement of this book. There is much valuable material he covers in the book which I have not reviewed in detail. Though a short work, it is monumental for the depth and breadth it covers, and for the coherency of theme on the growth of knowledge woven from history, art, and science. Rather than dispensing false profundities as is so commonplace these days, The Ascent of Man provides us inspiration from truth.

Recent episodes of Electric Chapter Lab:

The Ascent of Man, Chapter Eleven

The Ascent of Man, Chapter Ten

The Ascent of Man, Chapter Nine

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“Knowledge or Certainty”

Welcome to the eleventh episode of Electric Chapter Lab. Today we shall continue our review of The Ascent of Man.

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Knowledge or Certainty

In Chapter Eleven, Dr. Bronowski mixes epistemology with physics, and ends on a point of ethics. I agree with his conclusions, but his path to reach them is a little dubious in parts.

On the first page of the chapter, Bronowski states:

“There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy.”

I think this is true, and the most important lesson of the book so far. The first sentence in this quotation is an expression of fallibilism, as it is called in epistemology. Unfortunately, Bronowski undercuts himself by attempting to support this thesis with Quantum Mechanics, which has little to do with it.

In the first part of the chapter, he devotes a few pages explaining electromagnetic waves on a middle school level. He also mentions that the x-ray diffraction technique, invented in 1912 by Max von Laue, uses x-rays to directly image atoms, demonstrating that atoms are real and that x-rays are electromagnetic waves.

After discussing German university life in the 1920s, Bronowski arrives at Heisenberg’s Uncertainty Principle. But Bronowski is thrown off by the name, and it does not appear he understands what it is. The Uncertainty Principle is not a principle: rather, it is a physical law, and it is not fundamentally about uncertainty; a better name for it in English would be the “Unsharpness Relation” which is closer to the German word. This law is a result of wave mechanics, not particle behavior. Bronowski wants to rename it the “Principle of Tolerance”, as in we have some error tolerance for knowledge, and we should tolerate variation of information and eschew dogma. It’s a nice thought, but unfortunately this has nothing to do with Uncertainty Principle in physics. The fact that humans cannot know every datum in the Universe was realized long before Werner Heisenberg.

The last section of the chapter describes Leo Szilard, who realized a kind of chain reaction could split atomic nuclei, and his efforts to prevent the weaponization of this knowledge. Bronowski closes the chapter with the important point that tragedies like the Holocaust are the kind of things which happen when “people believe that they have absolute knowledge, with no test in reality ….” He is warning the world that “we have to cure ourselves of the itch for absolute knowledge and power.”

Recent episodes of Electric Chapter Lab:

The Ascent of Man, Chapter Ten

The Ascent of Man, Chapter Nine

The Ascent of Man, Chapter Eight

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“World within World”

Welcome to the tenth episode of Electric Chapter Lab. Today we shall continue our review of The Ascent of Man.

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World within World

In Chapter Ten, Dr. Bronowski discusses pre-1920s atomic physics. My review here is a little longer than usual, as I do have some criticisms, but I close on one of his strongest theses in the book.

Bronowski opens the chapter by discussing Mendeleev’s discovery of the periodic relation amongst the elements. But inside this interesting story is a small point of irritation: Bronowski refers to Mendeleev as a “prophet” and uses the phrase “Mendeleev prophesied”. I know he is trying to convey Mendeleev’s genius through analogy, but this language has the potential to confuse people. A prophesy is an invalid truth-claim based on zero evidence, which is not what Mendeleev was doing; he was guessing that a certain pattern would continue, based on quite a bit of evidence–an incomplete picture of a pattern. The danger of abusing language like this is that some people get the impression that Biblical-style prophecy is just as legitimate as scientific conjecture because they are somehow the same thing (which they are not).

Later on, Bronowski tries to connect late Nineteenth and early Twentieth Century visual art with physics. He claims that the artists are trying to depict the structure of the world, just as physicists are trying to study it. I think Bronowski sees what he wants to see here. I could as easily say that the artists of the time were denying the structure of the world, since it was over-simplified and flattened into two dimensions.

There is another comparison, between paintings and scientific papers, that Bronowski makes and which I think is totally backwards and wrong. He writes: “There are two clear differences between a work of art and a scientific paper. One is that in the work of art the painter is visibly taking the world to pieces and putting it together on the same canvas. And the other is that you can watch him thinking while he is doing it. … In both those respects the scientific paper is often deficient.” The kind of painting he describes sounds like the work of an amateur, unless the painter is using a very specific stylistic filter, like Impressionism. But normal realist art is opaque to technique, which is a very measure of skill. On the second point, it is the job of the scientific paper to “take the world into pieces”, or analyze, and lay it out in a logical way to make it clear. In other words, good painting is representative and illustrative, whereas a good paper is analytic and lucid. But you might not think that if you saw enough clumsy paintings and read enough obfuscatory papers.

Bronowski, when discussing the discoveries of Niels Bohr, makes another mistake. He says that Bohr “made the modern image of the atom.” The problem is that the Bohr model hasn’t been our image of the atom since 1925.

In an earlier episode of Electric Chapter Lab, I disagreed with Bronowski’s portrayal of theories as analogies. In this chapter, Bronowski makes the claim again in regard to atomic theories. He says “… when it comes to atoms, language is not describing facts but creating images.” If that were true, we would merely have atomic art rather than atomic theories. Fortunately, we have the language of mathematics and a surrounding cloud of technical English (or German, or whatever) which can and does describe facts. Bronowski continues: “When we step through the gateway of the atom, we are in a world which are senses cannot experience.” But there is nothing particularly special about this “gateway”–his statement holds true for Earth’s interior, the center of stars, distant galaxies, events in history, and almost everything else. Much of the information we obtain is through tools which augment our senses. He goes on: “… we only try to picture it [inside atoms] by analogy …. But all our ways of picturing the invisible are metaphors …. The models are meant to show, by analogy, how matter is built up.” I would say that metaphors and analogies are inaccurate by definition; sometimes so inaccurate that the picture they produce can lead you astray. When the Rutherford Model of the atom was proposed, I believe that scientists thought atoms really could be like tiny planetary systems, that there were literally small spheres orbiting some heavier central sphere. Of course they understood this was a model, but they were hoping it was an accurate model. Now we have a better one which is tested to extreme degrees of accuracy, demonstrating that the model contains facts, not a collection of image-based metaphors. I will agree with Bronowski in one respect though: that atoms are bizarre objects completely different from the larger scale objects we encounter in everyday life; but that does not mean drawing an accurate picture of them is impossible or inconceivable to our senses–it does mean that using analogies in science education can lead to significant misconceptions in the mind of the learner.

But let us move on to an important and interesting section of the chapter. Ludwig Boltzmann defined viewed entropy as a measure of disorder, whereas previously it had been viewed by Rudolf Clausius as energy inaccessible for work. Boltzmann’s equation, S = K log W, expresses a simple relation: entropy is the logarithm of the probability of a state multiplied by a constant (Bronowski does not indicate what the constant, K, is). Here, probability refers to a kind of logical possibility (rather than credence or frequency). There are vastly many more possible disordered states than ordered ones, so we express this by saying that ordered states are “improbable”. Boltzmann discovered a “statistical law” which says that “order tends to vanish”. This is an important concept in contemporary physics, and Bronowski goes on to make a further point which is quite important for biology as well. He says that although the probability of any particular complex arrangement of atoms, such as Bronowski’s body, is so small as to be basically impossible when the whole Universe is the sample space, this conception gives the wrong impression. Bronowski correctly points out that we should be considering a more restricted, relevant sample space: the previous causal steps. “The stable units that compose one … stratum are the raw material for random encounters which produce higher configurations, some of which will … be stable. So long as there remains a potential of stability which has not become actual, there is no other way for chance to go.” He calls this concept stratified stability, and it explains how improbably ordered states can arise in anti-entropic islands over time.

Recent episodes of Electric Chapter Lab:

The Ascent of Man, Chapter Nine

The Ascent of Man, Chapter Eight

The Ascent of Man, Chapter Seven

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“The Ladder of Creation”

Welcome to the ninth episode of Electric Chapter Lab. Today we shall continue our review of The Ascent of Man.

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The Ladder of Creation

In Chapter Nine, Dr. Bronowski discusses the theory of biological evolution.

Bronowski thinks there is a common reason as to why Evolution was conceived distinctly twice by two different men at the same time in the same culture. Unless I missed it, he doesn’t spell out what that main reason is. He does note, though, that both Darwin and Wallace were inspired by “Essay on Population” by Thomas Malthus.

The bulk of the chapter is spent on the personal stories of Charles Darwin and Alfred Wallace.

There is also some discussion of Louis Pasteur. In the 1860s, Pasteur falsified the Spontaneous Generation Hypothesis. He also discovered chirality (handedness of molecules) in chemistry, and established that life uses only one (which Bronowski does not name).

Near the end, Bronowski recounts some speculations about how life began on Earth, which seem quite dated compared to what we know now. (Perhaps they happened on other planets that way, but these scenarios do not appear suitable for Earth.) Oceanic hydrothermal vents are not mentioned.

Lastly, he notes that all life on Earth uses the same genetic code, despite it being not the only possible code-type, which suggests a common ancestor. However, he goes on to state that this implies “life began” only once (presumably he is referring to pre-biotic replicators which lead to our specific nucleotides). I do not understand that reasoning. Could it not be that there were several types of replicators, all of which were out-competed by our line, and thus subsequently went extinct? Bronowski goes on to say if any new arrangement of self-replicating molecules formed, they would not be able to link to the ones already in wide-spread use. But in the very next sentence, he says that “no one” thinks life is still forming on Earth, despite the previous sentence which claimed that life could form, but just be blocked by the type already in use. So my question is this: Could it not be the case that pre-biotic replicators are forming continually in some ideal environment, but they are also continually blocked and torn apart by the pre-existing biology, which operates on a much faster time-scale than the multi-megayear processes required to form a biome? If this could be the case, it would obviate the claim that the beginning of life was a singular, low-probability event.

Recent episodes of Electric Chapter Lab:

The Ascent of Man, Chapter Eight

The Ascent of Man, Chapter Seven

The Ascent of Man, Chapter Six

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