Biology to Learn

This is the sixth posts in the things to learn series. See the intro or the last post about biology vs. physics. This post lists interesting questions and topics in biology.

• What is life? 
• What is the basic architecture of a sample single-celled organism?
• How does life resist entropy internally and maintain order?
• Feedback systems: See Book Review: Design Principles of Biological Circuits
• How is energy passed from light to plants to animals, and how is it used by cells? (See also my carbon poem) 

• DNA and Genes
• Expression - How does the genetic message go from DNA to RNA to proteins?
• How do things like genetic dominance work at the chemical level?
• Reproduction - How does DNA replicate? How does it ensure variation? It's almost paradoxical how much effort life spends to preserve DNA and then also to mix it up. 
• Multiple swaps happen during meiosis
• How are traits inherited? (From Mendelian single-gene traits to more complex multi-gene traits)
• Differentiation - How do cells differentiate during fetal development?
• Initial impetus based on amount of fluid detected in egg/fetus, which then sets off chain reaction where genes signal to other genes. (Seems almost recursive. How did this process evolve?)
• A bit on modern techniques for editing DNA
• Old tech to transfer genes from one organism to another
• CRISPR
• Bigger picture of genetic differences. What does it mean that humans share ~50% of their DNA with a banana or 99.9% of their DNA with each other? How much do people differ from each other? What does that mean? How relevant is the non-coding DNA. 
• Seems us humans are not really 99.9% the same. Even just in coding DNA, letter differences change whole words and CNVs repeat words.
• Practical things can one learn from getting your DNA test 
• What genes led humans to be so different than e.g. chimpanzees. How a small number of genes can make a large difference in the brain's development. How non-coding DNA affects things. 

• Evolution
• Quantitative evolution -  Rates of mutations of DNA of different organisms. How long it takes for an adaptive gene to spread in a population. To what extent can the path of evolution be traced?
• The possible origins of the first life
• The role of epigenetics 
• Philosophy of evolution
• See Stanford articles on evolutionary genetics and teleological notions in biology
• What level evolution occurs at and how animals cooperate (see The Selfish Gene)
• Evolutionary psychology - how much actual evidence vs. speculation. Seems in many areas the brain is general purpose and people can adapt without genetic mutations.
• Related: philosophical interpretations of human nature

• The brain
• How can thoughts and memories arise from neurons? (This is understood to a certain extent.)
• How does consciousness work? (Difficult question!)
• How do Buddhist meditative views on consciousness relate to the scientific nature of the brain. (See Why Buddhism is True)
• To what extent are different animals conscious? Very simple animals (e.g. hydras) are not, and mammals appear to be but what about in-between?
• How did and does the brain develop (evolution, culture, nature, nurture)
• What happens to the brain during sleep?
• Why is it so important for health?
• Can dreams be interpreted as random neurons firing?
• To what extent is the brain hardwired when born vs. a system that learns? 
• Brain starts in very flexible state, but people eventually lose the ability to learn things like vision and speech. Some people can control extra fingers (See polydactyly.) What else could be wired to brain? Brain needs to be general purpose to have evolved.
• Computational neuroscience - how does the brain compare to artificial neural networks? Besides direct neurons firing, what else in the brain is used for processing?
• Behavioral neuroscience - To what extent does understanding the physical mechanisms of the brain help with understanding human psychology? In general, can the mind be viewed as a fully operating layer or are there many leaky abstractions?
  
• The human body and practical health
• Digestion and nutrition
• What makes a balanced diet?
• Metabolism rates and and people's weights. How would skinny people have fared in hungrier times? (See also The Hungry Brain)
• Infection and disease
• how bacteria and viruses spread
• how the layers of the immune system works
• how allergies develop and why they're more common now
• Exercise
• Why it's beneficial
• What practices for most benefits?
• How muscles strengthen and weaken 
• Answering health questions - the fundamentals to know + search skills to find answers
• The connection between psychological wellbeing and physical health
• Modern world - evaluating the risks that new substances (e.g. Teflon, BPA) may pose to human health
• Teeth - how cavities develop and best practices for preventing them
• Besides sugar, which foods are most harmful? How long does it take for decaying processes to start occurring? 
• Can one reduce prevent the mouth from being colonized by harmful bacteria?
• Does flossing work in practice? What are alternatives
• What other treatments exist (e.g. Silver diammine fluoride)
• Sleep - what happens in the body during sleep, best practices for sleep
• Big picture topics 
• Big picture view of evolution (See Big History Course or more poetically, The Goddess of Everything Else)
• Numbers in biology (See book.bionumbers.org)
• Patterns in biology (See Scale)

Biology vs. Physics

This is the fifth post in the series on things to learn. See the intro or the last post on learning physics.

The natural sciences are divided into two branches: the physical sciences (primarily physics and its derivatives) and the life sciences (a.k.a biology). Biology is different than physics in many ways, which affect how one learns it:

• Less Math - Math is fundamental to all of physics but it's more incidental in biology. This can make biology easier to learn for many people.
• More complexity - As challenging as physics is, it's ultimately about simple concepts. But biology is about life, which is complicated.
• Textbooks filled with terminology and small details can make learning biology more tedious. However I think there may be a way to focus more on the overall concepts involved than on the exact terminology and details. When learning for general curiosity, you don't need to know every exact term, you can just learn the terms that will be repeated enough to be worth learning. (See XKCD's thing explainer for an exaggerated example of explaining concepts with less terminology.)
• Unknown frontier - Physics has already solved most areas that a layman would be interested in. The current frontier of physics deals with problems that would be hard a non-physicist to relate to, and it would take years of learning to understand them. Meanwhile biology is filled with unsolved questions in every area from neuroscience to nutrition to genetics to diseases, and one encounters these issues right away. 
• Update: this point is debatable since there are unsolved questions in physics that a layman would be interested in.
• Practical - If you're not an engineer you're unlikely to use knowledge of physics for anything practical. But biology topics like nutrition and disease are relevant to living longer and healthier lives.

There are other ways that physics and biology differ:

Inherent or accidental?

It seems that many parts of physics could be intuited based on other principles and couldn't be any other way:

• Falling objects - Galileo argued against the Aristotelian idea of motion (that heavier objects fall faster) not only with experiments but by pointing out the logical paradoxes that would result.
• Inverse-square law - While one could imagine forces decreasing in other ratios, decreasing in proportion to r² seems the most logical since a force radiating out from a point will spread out according to the formula for a sphere's surface (4πr²).
• Relativity - While most people wouldn't intuitively think of Special Relativity, it seems Einstein was able to recognize that it was the "only way" possible. He was able to derive this based on a deep understanding of the implication's of Maxwell's equations, and he may not even have been aware of the Michelson-Morley experiments.

Questions in physics are still resolved through experiments, but maybe this is to demonstrate the truth to those who don't have the right intuitions of the way nature "needs" to be. When Einstein was asked what if the experiments had disproven his theory of General Relativity, he said "then I would have felt sorry for the dear Lord. The theory is correct." While physics cannot just be pure deduction like mathematics, it's the closest one can get. The eventual goal of physics is to find the theory of everything from which everything else is derived.

Biology however deals with the complex messiness of life, and there's many ways to be a living thing. Scientists can may make predictions based on the data they have, but they can't derive how systems "must" be. Living things are "accidental" in the Aristotelean sense of having traits that they happen to have but could lack.

Purpose 

Ancient and medieval physics used teleological explanations as Aristotle emphasized the "final cause" (or purpose) as one of the "four causes" to explain the way things are, and argued against Democritus who rejected it. Modern physics, starting with Francis Bacon, returned to the physics of Democritus and dropped "purpose" from consideration. Since Isaac Newton, the motion of heavenly and earthly bodies is explained with simple physical laws, without reference to any goal or "natural place" of matter. 

Unlike rocks or stars, living things act with purpose. Even a simple bacterium seeks food, evades predators and maintains its internal state. While scientists no longer use theological explanations to explain why organs and organelles have certain functions and designs, these elements still exist and are worthy of explanation. Some use the term teleonomy to distinguish modern explanations of biological purpose from earlier ones.

In short physics is about mathematical explanations for "simple" things from atoms to galaxies, while biology is about the complexity of life, with all its purpose. 

Learning the Physical Sciences

This is the fourth post in the series on things to learn. See the intro or the posts on math and software development.

Should Studying Science be Mandated?

Most people won't become scientists so learning science is about satisfying curiosity about how the world works and came to be, not about learning a practical or career-oriented topic. Beyond the most essential understanding of how the word works, the physical sciences should be an optional part of the K-12 curriculum. Students who are interested in science can be encouraged to learn it since some of them may appreciate the opportunity and a fraction of them will later use it in their careers. Those who are uninterested are unlikely to become scientists themselves, but they can always catch up later if they desire to.

Once a student commits to learning a topic in high school or college, they can force themselves to continue learning it even when it's difficult, since they want to do well in the course. This is the one benefit of schools - they provide a structure or incentive system where people can learn. Once someone leaves school and is just learning on the side for enlightenment, they're less likely to "force" themselves through difficult topics. However, when you're learning on your own, you can choose to learn the most interesting topics.

Learning the Concepts in Science

If you're learning science just to satisfy curiosity, you don't need to learn every technical detail covered in textbooks.

Q: Can you learn physics without advanced math?

A: I think so:

• Many areas of physics (such as mechanics) can be understood with basic algebra and maybe a sprinkle of simple calculus.
• Even in other areas, it seems one can get at at least a partial conceptual understanding without covering all the mathematical details.

While a researcher or engineer may need to know all the mathematical nitty gritty, someone learning physics for knowledge can likely skip over some of these details. In the past it was even possible to make significant discoveries in physics with limited knowledge of math. For example Michael Faraday was "one one of the most influential scientists in history" despite the fact that "his mathematical abilities... did not extend as far as trigonometry and were limited to the simplest algebra". (Though even there, James Maxwell's equations were needed to fully understand the implications of Faraday's discoveries.) Physics became more complex over time, so later developments in physics require more math to truly understand them, but one can still learn a simpler version of any topic.

Books that cover concepts in Physics

These are books that give an overview of physics and its development:

• Seven Ideas That Shook the Universe - different paradigms in physics: Copernican astronomy, Newtonian mechanics, energy and entropy, relativity, quantum theory and conservation principles & symmetries.
• The Evolution of Physics (By Albert Einstein and Leopold Infeld) - As summarized by the table of contents, it covers The Rise of The Mechanical View; The Decline of the Mechanical View; Field, Relativity; and Quanta. Slightly similar to the above book, though from Einstein's perspective.
• The Character of Physical Law (by Richard Feynman) - Instead of covering all of physics, it goes through certain ideas as examples of physics. This is the written version of a series of lectures by Feynman so it isn't as edited as the above books, but it contains Feynman's unique style.

Specific Topics in Physics

Here are some interesting topics in physics they seem worth learning more about.

• Mechanics - Force & Motion & Inertia
• The basic formulas and their calculus.
• Example question: Intuitively, why is Kinetic Energy (KE) proportional to v²when momentum is proportional to v (velocity)?
  Answer: Lets' say you want to stop a frictionless moving car by putting a friction block on which drags on the ground with a constant force. A car going 2x as fast will take 2x as much time to stop since, as expected since it has 2x the momentum. However it will take 4x as much distance to stop the car. All that distance involved the same rate of friction heat creation, so the car going 2x as fast must have 4x the KE. Similarly if you want to drop a block and have it go 2x as fast as another block, you'll need to raise it to 4x the height. This was also a controversy between followers of Newton and Leibniz, see Vis Viva.
• How/why is inertia and conservation of momentum so fundamental in all of physics?
• Gravity (Newtonian)
• How Newton discovered the law of gravity from a better understanding of motion.
  (I.e. how Newton built on Galileo to create his Newton's laws of motion, then connected them with Kepler's laws of planets and then connected that with the moon's motion and universal gravitation.)
• Basic math of satellites and planets in orbit
• Key concepts in general relativity
• Electromagnetism
• Understanding what electric and magnetic fields are are and how they interact with charged particles.
• How special relativity resolved issues raised by Maxwell's equations. 
• Interesting when reading Einstein's writings, how strong his intuition was to avoid any special frames of reference and how this took priority over other intuitive ideas such as about absolute time...
• Thermodynamics
• What is entropy? Besides the fundamental meaning for particles, how does it affect non-thermodynamic order? Whats was the entropy of the universe initially? How does gravity affect entropy? (See also heat death paradox, as well as this question.)
  

  Understanding Physics (by Isaac Asimov) gives basic explanation the laws of thermodynamics. First law is about the "absolute" store of energy. But energy can only be used when it flows from "high" to "low". And over time differences even out so entropy increases. Book has this more philosophical observation:
  

  We thus find there is an odd and rather paradoxical symmetry to this book. We began with the Greek philosophers making the first systematic’ attempt to establish the generalizations underlying the order of the universe. They were sure that such an order, basically simple and comprehensible, existed. As a result of the continuing line of thought to which they gave rise, such generalizations were indeed discovered. And of these, the most powerful of all the generalizations yet discovered — the first two laws of thermodynamics — succeed in demonstrating that the order of the universe is, first and foremost, a perpetually increasing disorder.

• How does "information" as a physical concept connect to this? (see wikipedia and stanford article.)

• Is the second law of thermodynamics more "proven" than other natural laws?
• How the theoretical science developed from the technological development of steam engines (and compare with how computers developed) 
• Practical applications in everyday life (e.g opening fridge won't cool room)
• Nuclear physics
• The nuclear bonds (and how E=MC² not that relevant).
  Compare nuclear bonds with chemical energy.
  (Bonus: the weak force and how it relates to electromagnetic force) 
• Quantum mechanics - to what extent can it be understood by a layman?
• Consider reading parts of Scott Aaranson's Quantum computing since Democritus (or the lecture notes)
• Interpretations of quantum indeterminacy
• See lecture notes
• Bohemian mechanics (pilot wave theory)

Other topics in the physical sciences

• Astronomy & astrophysics - How the universe developed
  The formation of all elements (Stellar nucleosynthesis). The cycle of stars. How matter regrouped after stars exploded.. (See Wikipedia on Stellar population.)
• Chemistry
• how does the number of protons/electrons determine the properties of elements?
• Much of this is more basic chemistry, as seen in repetition in the periodic table
• Sometimes the specifics of how properties like color are determined can involve more complex areas, e.g. need relativistic quantum mechanics to explain why gold is gold-colored instead of silver. 
• How does the structure of electrons in chemical compounds determine their properties? 

• Earth science
• Development of earth
• Earth's magnetism
• Global warming

Coronavirus - Evidence and Restrictions

• When learning topics of theoretical interest, one should learn from established science. There's enough established science that's interesting, why bother with the speculative stuff? However, when something is practically relevant but the facts are not known, you can't just wait for things to be proven. You need to use the best info and probabilities you have and act accordingly. This is something many people fail to realize.
• For example, the WHO initially said there was "no clear evidence of human-to-human transmission of the novel coronavirus". Even if there had been no solid evidence, it would still make sense to suspect human-to-human transmission and take proper precautions instead of "not recommend[ing] any specific health measures for travellers" and being "against the application of any travel or trade restrictions on China" (link).
• The WHO recommendations about masks was even more "radically conservative". They continued to insist for months that there was no evidence that wearing masks would help prevent the spread of the virus. But one can't wait for a double-blind study to test whether masks work. One needs to look at the empirical data available, such as the reduced spread of the virus in mask-wearing countries, or the best arguments available, such as the plausible reduction in the spread of droplets when people wear masks.
• If people had acted earlier in those cases, many lives could have been saved. But it doesn't mean we should now go the opposite extreme and recommend everyone remain in total isolation for months.
• There is reasonable evidence that the virus primarily spreads from being indoors with someone for a while or from things like shouting and singing (besides coughing and sneezing of course). People who are careful could still meet outside in certain cases.
• Many people who live alone are both very unlikely to have the virus and very unlikely to spread it to the elderly or other high-risk people. Such individuals shouldn't feel like they're in solitary confinement but should be able to meet with specific individuals in a careful manner. 
• Governments should not just add every restriction possible and think this will keep people safe. There's a Talmudic statement "כל המוסיף גורע" - "whoever adds [restrictions], detracts" since people will treat all restrictions in the same manner and not be careful even for the important ones. Government policies need to focus on strongly enforcing important restrictions while allowing other low-risk activity to resume.

Science - New or True?

• People often quote news articles about recent developments in science as if a new Truth was discovered. Health studies are a particularly popular topic.
  
  
• However, most studies are false, and most news articles (particularly headlines) misquote or exaggerate them, and most people misquote or exaggerate the news article or headline. The probability the person is saying something true is low, say 40% * 40% * 40% = 6% (± 5%). 
  
  
• If one wanted to learn about the world, it would be better to learn more established science that is very likely to be True.
• While books and courses are a good way to learn knowledge, people are often interested in short tidbits instead. For example, see all the blogs and magazines that just publish the same thing about cleaning your house or being productive.
• It's less common that media or people discuss established facts in science. But people should feel free to publish, share and discuss interesting things they've found out about nature. While it may not be new it's more likely to be true.

Google picking

• P-hacking is fishing around in data until you find a "significant" p-value so you can find an exciting claim, publish your paper and get tenure
• Let's define Google-picking as trying out different Google searches until you find a result that says what you want it to say
• To deal with issues like P-hacking, some institutions now require publication of all experiments and analysis performed or pre-registration of the proposed studies
• If someone cites an obscure internet result to support their claim, they could be suspected of Google picking and should be required to "publish" what searches they performed
• In all cases, the claim needs to be evaluated on it's own merit (and one's own searches) regardless of how the data backing it was discovered