2318: Dynamic Entropy
Title text: Despite years of effort by my physics professors to normalize it, deep down I remain convinced that 'dynamical' is not really a word.
This is another one of Randall's Tips, this time a Science Tip. This time it is a bit special since it came less than three weeks after another Science Tip: 2311: Confidence Interval (which was itself the first time that a non-Protip Tip type has been re-used). This is the first time a type of tip (that was not a Protip) has been used for two "tips comics" in a row.
This Science Tip suggests that if you have a cool new concept, you should call it dynamic entropy, hence the title.
Dynamic programming is a mathematical optimization method and computer programming method developed by Richard Bellman in the 1950s. The History section of the Wikipedia article contains the full paragraph from Bellman's autobiography that contains the quote that is in the comic strip. Bellman describes how he was doing mathematical research funded by the military at a time when the Secretary of Defense had a literal pathological fear of the word "research", and by extension, "mathematical". Bellman borrowed the word "dynamic" from physics as being both accurate for his work and as a word that in plain English has positive connotations and is never used in a pejorative sense (expressing contempt or disapproval). The word "dynamic" itself comes from the Greek dynamikos, "powerful", which is a positive meaning in itself, and has been applied to topics in physics that are related to motion and forces and used in ordinary English to refer to things that exert power, force, growth, and change (dynamo, dynamite, and as an adjective). Even though those things aren't always good, when they're bad, we use other words instead (e.g. cancer undergoes metastasis, not "dynamism").
Entropy is a term from physics, specifically statistical mechanics, describing a property of a thermodynamic system. When Claude Shannon developed a mathematical framework for studying signal processing and communications systems, which became known as Information theory, he struggled to come up with a proper name for one mathematical concept in his theory that quantified amount of noise or uncertainty in a signal. Computer scientist John von Neumann noticed the similarity of the equations with some in thermodynamics and suggested, "You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, no one really knows what entropy really is, so in a debate you will always have the advantage." (see History of information theory).
The naming of dynamic programming and of entropy in information theory are both examples of scientists choosing a name for what were at least partially very non-scientific seeming reasons. In one case because it has only positive and no negative connotations in plain English. In the other case because there is much confusion over the meaning of the word so Shannon would be free to adopt it in a new context. Randall is claiming that would make them great to put together to name some new concept; the combination will mean whatever the creator wants it to mean (even able to change mid-debate), and never sound bad the way that e.g. cold fusion has come to be.
Even though the caption implies that "dynamic entropy" would be available as a new name, it has actually been used in physics, probability, computer science, and even the term "dynamical entropy" in physics and bioscience.
In the title text Randall mentions that, even though his physics professors have continued to use the word "dynamical", "trying to normalize it" by repetitive usage, he remains convinced that it is not really a word. Presumably he doesn't like that it has two suffixes used to make words into adjectives, -ic and -al, as if "dynamic" wasn't already positive enough. The Free Dictionary discusses how -ic and -ical suffixes are confused in many common words and explains their different uses.
- [One panel only with text and a few lines and arrows. There are two columns each with a heading. Beneath each heading is a quote written on four lines. Below the quote, in grey font, and indented, starting with a hyphen, with the text aligned to the right of this are five lines of text. This explains who the quote belongs too and where it was stated (in brackets at the end). From the bottom of each of these two gray text paragraphs gray curved arrows goes down to two gray lines. Below each of these two lines are one large word per line. They are again in black text.]
- "It's impossible to use the word 'dynamic' in the pejorative sense... Thus, I thought 'Dynamic Programming' was a good name."
- - Richard Bellman, explaining how he picked a name for his math research to try to protect it from criticism (Eye of the Hurricane, 1984)
- "You should call it 'Entropy'... No one knows what entropy really is, so in a debate you will always have the advantage."
- - John von Neumann, to Claude Shannon, on why he should borrow the physics term in information theory (as told to Myron Tribus)
- Dynamic Entropy
- [Caption below the panel:]
- Science Tip: If you have a cool concept you need a name for, try "Dynamic Entropy."
Many of Buckminster Fuller's designs and works were associated with the word "dymaxion", a combination of the words "dynamic", "maximum", and "tension", all words that Fuller himself used a lot in talking about his work, and which are words that simultaneously have use in science and positive connotations in lay English.
- Allegrini, P., Douglas, J. F., & Glotzer, S. C. (1999). Dynamic entropy as a measure of caging and persistent particle motion in supercooled liquids. Physical Review E, 60(5), 5714, doi: 10.1103/physreve.60.5714.
- Asadi, M., Ebrahimi, N., Hamedani, G., & Soofi, E. (2004). Maximum Dynamic Entropy Models. Journal of Applied Probability, 41(2), 379-390. Retrieved June 11, 2020, from www.jstor.org/stable/3216023
- S. Satpathy et al., "An All-Digital Unified Static/Dynamic Entropy Generator Featuring Self-Calibrating Hierarchical Von Neumann Extraction for Secure Privacy-Preserving Mutual Authentication in IoT Mote Platforms," 2018 IEEE Symposium on VLSI Circuits, Honolulu, HI, 2018, pp. 169-170, doi: 10.1109/VLSIC.2018.8502369.
- Green, J. R., Costa, A. B., Grzybowski, B. A., & Szleifer, I. (2013). Relationship between dynamical entropy and energy dissipation far from thermodynamic equilibrium. Proceedings of the National Academy of Sciences, 110(41), 16339-16343.
- Słomczyński, W., & Szczepanek, A. (2017). Quantum dynamical entropy, chaotic unitaries and complex Hadamard matrices. IEEE Transactions on Information Theory, 63(12), 7821-7831, doi: 10.1109/TIT.2017.2751507.
- Chakrabarti, C. G., & Ghosh, K. (2013). Dynamical entropy via entropy of non-random matrices: Application to stability and complexity in modelling ecosystems. Mathematical biosciences, 245(2), 278-281, doi: 10.1016/j.mbs.2013.07.016.
- Atmanspacher, H. (1997). Dynamical entropy in dynamical systems. In Time, temporality, now (pp. 327-346). Springer, Berlin, Heidelberg, doi: 10.1007/978-3-642-60707-3_22
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