Take probability models seriously, but not literally

Last week's Science had a feature article about several nurses who were convicted of murder in Europe based on statistical arguments regarding the number of babies who died under their care.  Some of these arguments appear to have been decisively debunked by statisticians not originally involved in the cases.  There is a sidebar article by the same author (Cathleen O'Grady) on mothers who were tried for the murders of their own children, again based on questionable statistical arguments.

These episodes are striking, given that I am currently reading a book by physicist Erica Thompson, Escape from Model Land:  How Mathematical Models Can Lead Us Astray and What We Can Do About It (Basic Books, 2022).  She argues that mathematical models always make simplifications and assumptions that divorce them from the real world; and while the modeling exercise may be of great instructive value, one must often be very careful not to claim that the model output represents reality.  In other words, once you step into "model land", and do your modeling exercise, you must not forget to step back out into the real world, and not mistake model land for reality.  The way I would put it is that models deserve to be taken seriously, but not literally.  In the case of the shoddy statistics that put innocent nurses and mothers in prison, those analyses should not be taken either seriously nor literally. 

Hamiltonian mechanics and Maxwell's relations in thermodynamics

This is my last post of 2022.  I just wanted to share that I recently stumbled upon a talk, from about a year ago, on youtube by Prof. John Baez, "Classical Mechanics versus Thermodynamics".  He seems to have discovered a connection/analogy between Hamilton's equations in analytical dynamics with Maxwell's relations in thermodynamics.  I had always thought of these topics as long settled parts of classical physics, but I am delighted that people can still find new sources of insight into them.  I found the talk riveting.  Apparently there are more details on his blog.

And with that, may all DTLR readers enjoy a wonderful 2023!

Important physicists who were medical doctors

Physics did not become a separate profession (as opposed to natural philosophy) until probably the 18th, if not 19th, century.  For much of the early history of physics, its practioners and researchers often had formal training in other learned professions.  One such profession is that of medicine.

With only minimal research, I tried to jot down the names of important physicists who had substantial training in medicine.  Not all of them actually practiced medicine, despite their education, but several did.  Here is what I came up with, in approximate chronological order:

• Nicolaus Copernicus (1473-1543)
• Girolamo Cardano (1501-1576)
• William Gilbert (1544-1603)
• Daniel Bernoulli (1700-1782)
• Thomas Young (1773-1829)
• Julius Robert von Mayer (1814-1878)
• Hermann von Helmholtz (1821-1894)

Can you think of others who belong on this list?

 

Addendum, March 25, 2023.  Jennifer Coopersmith's book, Energy, the Subtle Concept (revised edition, Oxford University Press, 2015, Appendix III) makes clear the following individuals, contributors to thermodynamics, should be added to the above list:

• Hermann Boerhaave (1688-1738)
• Joseph Black (1728-1799)
• Pierre Louis Dulong (1785-1838)
  

Addendum, October 22, 2023.  I recently learned that Galileo Galilei attended medical school, but dropped out.  In fact, he did not complete a college degree at all.  However, Stillman Drake speculates that the definition of cause Galileo gives in his treatise On Floating Bodies is a take on an aphorism taught to medical students of the time.  See Drake's Cause, Experiment, and Science (University of Chicago Press, 1981) for details.

Physicists honored on US currency and coinage

Last year, I blogged about physicists, astronomers, mathematicians, and aerospace scientists and inventors honored on US postage stamps.  Today I'd like to tackle the even rarer phenomenon of physicists depicted on US currency and coinage.

Not surprisingly the list is very short.  Obviously, again Benjamin Franklin heads the list, as depicted on the $100 bill.  He is now joined by Dr. Sally Ride on a new American Women Quarter, issued this year.

If we expand our focus, as we did for the postage stamps, to include aerospace inventors, the Wright Brothers are depicted on the North Carolina  state quarter (2001), and their Flyer is also depicted on the Ohio state quarter (2002).  

Aside from these, I know of no other scientists, mathematicians, or engineers depicted on US currency and coinage, unless you count the polymath Thomas Jefferson.  Are there any that I missed?

Norton Critical Editions in natural science

Continuing a slight diversion that began with my November 2021 post on the Cambridge Companions series, let's consider independent publisher W. W. Norton's series of Critical Editions.   The Norton Critical Editions are annotated editions of classic works, mostly of literature, along with editorial apparatus including context and commentary.  Until recently I owned only one NCE, of Machiavelli's The Prince, and was not aware that any books in the series covered natural science.  I recently became aware that there are at least three NCEs on natural science:  two on biology, and one on physics and mathematics.  One is an NCE of James Watson's The Double Helix, edited by Gunther Stent (1980), and the other two are anthologies of selected writings of Isaac Newton (ed. by I. B. Cohen and R. S. Westfall, 1995) and Charles Darwin (ed. by P. Appleman, 1970; 3d edition, 2001).  If that is a complete list of NCEs in natural science, then it has been over 20 years since the last one was revised, while no others have been issued.

These books seem to be intended for use in humanities courses.  The volume on Newton, which I recently acquired, does have some technical material, but is not dominated by it.  And perhaps this explains why there are no other NCEs for physicists.  Too bad!

The 2022 Nobel Laureates in Science

The first week of October has been an exciting one, as usual, with the announcements of the Nobel Prizes, especially those in science.  DTLR readers know that I have a particular interest in connections between Nobel Laureates and fluid mechanics research, even though the prizes have rarely been awarded for work in classical hydrodynamics.  This year is no different, but at least two of the science laureates have familial connections to hydrodynamicists!

One of this year's physics laureates, John F. Clauser, stated in an oral history interview conducted 20 years ago with Joan Bromberg, that his father was a grad student of Theodore Von Karman's, and later became chair of the aeronautics department at Johns Hopkins.  Clauser states that "But all along the way, he always was trying to understand physics, and there were very strong similarities between the mathematics of fluid flow and the mathematics of quantum mechanics, and he didn't understand quantum mechanics. And he kind of pre-programmed me as the guy who might help try to solve the problem that he couldn't solve."  This appears in the very first paragraph of the transcript!  Further down in the transcript, Clauser returns to fluid mechanics, revealing that he himself is quite knowledgeable about it, discussing solitons, compressible flow, the subsonic-supersonic transition, and shock waves.

One of this year's chemistry laurates, Carolyn Bertozzi, has an older sister Andrea, who is a distinguished math professor at UCLA and works in fluid mechanics.  Andrea Bertozzi is co-author (with her doctoral advisor, Andrew Majda) of Vorticity and Incompressible Flow (Cambridge University Press, 2002). Incidentally, their father was an MIT physics professor.

Congratulations to all the 2022 Nobel Laureates in physiology/medicine, physics, and chemistry!

 

Electron fluidics

Last month in Nature there was a paper claiming to have observed vortex motion in an electron fluid.  The abstract describes the observations (imaged using a SQUID, or superconducting quantum interference device) as "surface-induced para-hydrodynamics, which mimics many aspects of conventional hydrodynamics including vortices".  Earlier this week the finding was described in a Physics World article by Isabelle Dume, to whom I owe the hat/tip.