History Biographies, History, Philosophy of Physics

[sbrothy]

Seems to be quite a lot of music threads in this forum. In that context this seems very apt:

Music, Immortality, and the Soul

(20 Sep 2024 / History and Philosophy of Physics (physics.hist-ph))

Music has been called the temporal art par excellence. Yet, as this paper explains, it is also the atemporal art par excellence. The contradiction is, however, only apparent, and a result of viewing music from two possible perspectives. That it has these two perspectives is the focus of this paper. In particular, the way in which these two aspects of music allow it to function as a kind of conduit between transcendent and immanent; immaterial and material. This can help explain the power of music to touch places deep in the soul (the part of us that transcends matter and time), that other forms of art struggle to reach. A somewhat similar debate occurs in looking at mathematics from an ontological point of view. In particular the treatment of the real numbers. There are curious properties of real numbers that seem to put them, like music, in the realm of the transcendent: in terms of the amount of information to specify them, one requires infinite computer time since there is no repeating pattern to their decimal expansions. One must simply evolve the sequence, working through it, despite the fact that it might have a perfectly situated home in Platonia. In other words, bringing them into this world demands a temporal element. We explore these and other links to a variety of issues in physics, ultimately arguing for dual-aspect monism."

EDIT: More and more I understand physicist's animosity towards philosophy when it flies so high it begins to talk about "souls" and "immortality". I mean maybe step down and out from your ivory-tower and walk for a while in normal people's shoes. Taking QM as a hostage to talk about reincarnation or something similar is just plain silly. I'm not saying this particular paper goes that far but, admittedly, some of the authors of these papers seem to have their heads in the clouds.

EDIT2: What I like are those philosophical papers that are unfortunately far apart when the author obviously understand the mathematics and makes some points QM interpretation-wise. But yeah, they aren't all that common.

 

[sbrothy]

Build up some inertia there and these two not only seem to fit together but also seem to be relevant considering contemporary news:

Emergence of echo chambers in a noisy adaptive voter model

(19 Sep 2024 / Physics and Society (physics.soc-ph); Adaptation and Self-Organizing Systems (nlin.AO))

Belief perseverance is the widely documented tendency of holding to a belief, even in the presence of contradicting evidence. In online environments, this tendency leads to heated arguments with users ``blocking'' each other. Introducing this element to opinion modelling in a social network, leads to an adaptive network where agents tend to connect preferentially to like-minded peers. In this work we study how this type of dynamics behaves in the voter model with the addition of a noise that makes agents change opinion at random. As the intensity of the noise and the propensity of users blocking each other is changed, we observe a transition between 2 phases. One in which there is only one community in the whole network and another where communities arise and in each of then there is a very clear majority opinion, mimicking the phenomenon of echo chambers. These results are obtained with simulations and with a mean-field theory.

Trust in society: A stochastic compartmental model

(19 Sep 2024 / Physics and Society (physics.soc-ph); Probability (math.PR))


This paper studies a novel stochastic compartmental model that describes the dynamics of trust in society. The population is split into three compartments representing levels of trust in society: trusters, skeptics and doubters. The focus lies on assessing the long-term dynamics, under `bounded confidence' i.e., trusters and doubters do not communicate). We state and classify the stationary points of the system's mean behavior. We find that an increase in life-expectancy, and a greater population may increase the proportion of individuals who lose their trust completely. In addition, the relationship between the rate at which doubters convince skeptics to join their cause and the expected number of doubters is not monotonic -- it does not always help to be more convincing to ensure the survival of your group. We numerically illustrate the workings of our analysis. Because the study of stochastic compartmental models for social dynamics is not common, we in particular shed light on the limitations of deterministic compartmental models.
In our experiments we make use of fluid and diffusion approximation techniques as well as Gillespie simulation.



And yeh, I'll stop for now.

 

[sbrothy]

Not really on-topic here but I remember someone, somewhere else, asking how to employ AI in practical teaching. Rather than adding noise to someone else's discussion I'll just leave this one here:

Democratizing Signal Processing and Machine Learning: Math Learning Equity for Elementary and Middle School Students

Signal Processing (SP) and Machine Learning (ML) rely on good math and coding knowledge, in particular, linear algebra, probability, and complex numbers. A good grasp of these relies on scalar algebra learned in middle school. The ability to understand and use scalar algebra well, in turn, relies on a good foundation in basic arithmetic. Because of various systemic barriers, many students are not able to build a strong foundation in arithmetic in elementary school. This leads them to struggle with algebra and everything after that. Since math learning is cumulative, the gap between those without a strong early foundation and everyone else keeps increasing over the school years and becomes difficult to fill in college. In this article we discuss how SP faculty and graduate students can play an important role in starting, and participating in, university-run (or other) out-of-school math support programs to supplement students' learning. Two example programs run by the authors (CyMath at ISU and Ab7G at Purdue) are briefly described. The second goal of this article is to use our perspective as SP, and engineering, educators who have seen the long-term impact of elementary school math teaching policies, to provide some simple almost zero cost suggestions that elementary schools could adopt to improve math learning: (i) more math practice in school, (ii) send small amounts of homework (individual work is critical in math), and (iii) parent awareness (math resources, need for early math foundation, clear in-school test information and sharing of feedback from the tests). In summary, good early math support (in school and through out-of-school programs) can help make SP and ML more accessible.

EDIT:

Oh, and to maybe "add some makeup to an ugly pig" (to slaughter a metaphor in translation) this one at least looks somewhat on-topic:

Majorana and the bridge between matter and anti-matter

This short essay aims to offer a discursive presentation of three scientific articles by Ettore Majorana highlighting the fundamental importance of one of them - the last one - for the investigation of the intimate constitution of matter. The search for evidence to support Majorana's thesis is the prime motivation of the conference "Multi-Aspect Young Oriented Advanced Neutrino Academy" at the G.P. Grimaldi Foundation in Modica, Sicily.

 

[sbrothy]

I don't know if this count as a "controversy" or downright plagiarism but it looks like Hans Christian Ørsted - whom every Danish schoolkid is taught is a national treasure up there with Niels Bohr as he supposedly discovered electromagnetism - apparently pretty much stole the idea from Gian Domenico Romagnosi (boldness added):

[...] It is sometimes assumed that he [Gian Domenico Romagnosi] found a relationship between electricity and magnetism, about two decades before Hans Christian Ørsted's 1820 discovery of electromagnetism. However, his experiments did not deal with electric currents, and only showed that an electrostatic charge from a voltaic pile could deflect a magnetic needle. However, as Joseph Hamel has pointed out, Romagnosi's discovery was documented in the book by Joseph Izarn, Manuel du Galvanisme (1805), where a galvanic current (courant galvanique) is explicitly mentioned]. [...]

The following information was gleaned from historum.com. While it might not be a creditable source I tried to verify the claims individually and they seem to be corroborated by the Springer article though it's behind a paywall and in Italian (I'm that good! Dunnng-Kruger Effect anyone?!). I provided the reference for completeness sake.

• A first paper written by Romagnosi¹ was published on the Gazzetta di Trento 3 August 1802
• A second paper written by Romagnosi² was published on the Gazzetta di Rovereto August 13 August 1802.
• Romagnosi, in October 1802, sent his paper to Paris (Academie des Sciences, 1802)³
• A private letter written by Romagnosi in 1827 ³, commenting on Oersted's experiment and claiming priority in the discovery of electromagnetism.

1.) In Italian
2.) Paywalled Springer link. In Italian.
3.) Seems to be mentioned in the Springer article but I don't have full access and I don't understand Italian.


Some additional "proof":


Romagnosi and Volta’s Pile: Early Difficulties in the Interpretation of Voltaic Electricity
Speculation and Experiment in the Background of Oersted's Discovery of Electromagnetism
Gian Domenico Romagnosi’s Forgotten Experiment on the Magnetic Effect of Currents in 1802

If this is true it is a very little known fact in Denmark and actually pretty embarrassing. I know this kind of thing goes on in science all the time but that really doesn't make it better.

EDIT: Admittedly, it could be an independent discovery. That kind of thing also goes on in science all the time.

EDIT2: Fixed link.

 

[sbrothy]

Book Review: 'Background Independence in Classical and Quantum Gravity', by James Read

Elegance, Facts, and Scientific Truths

I argue that scientific determinism is not supported by facts, but results from the elegance of the mathematical language physicists use, in particular from the so-called real numbers and their infinite series of digits. Classical physics can thus be interpreted in a deterministic or indeterministic way. However, using quantum physics, some experiments prove that nature is able to continually produce new information, hence support indeterminism in physics.

 

[pines-demon]

I do not know if this fits here, but in view of the recent Nobel Prize in Physics, this is an interesting video. Is John Hopfield giving a presentation in a conference in 1983 a year after his key paper on Hopfield networks:

Clearly in the words of a physicist. A spin glass Hamiltonian is used to explain it.

 

[pines-demon]

This semi-auto-biographical text is a great read:

• Whatever Happened to Solid-State Physics? - J.J. Hopfield, Annu. Rev. Condens. Matter Phys., 2014

 

[Hornbein]

This semi-auto-biographical text is a great read:

• Whatever Happened to Solid-State Physics? - J.J. Hopfield, Annu. Rev. Condens. Matter Phys., 2014

This site can’t be reached​

Check if there is a typo in whatever%20happened%20to%20solid-state%20physics

• If spelling is correct, try running Windows Network Diagnostics.

DNS_PROBE_FINISHED_NXDOMAIN

 

[pines-demon]

Updated

 

[sbrothy]

I was a little inebrieated but found this note in my pocket when I came home:

"Nobel chemistry, David Baker, John Jumper, Demis Hassabis, "something with proteins".

I need to sober up before I unpack that.

EDIT:

https://www.nobelprize.org/prizes/chemistry/2024/press-release/

Jumping the shark...

 

[pinball1970]

I was a little inebrieated but found this note in my pocket when I came home:

"Nobel chemistry, David Baker, John Jumper, Demis Hassabis, "something with proteins".

I need to sober up before I unpack that.

Nobel gases that do not really really react with anything, related to proteins?
Be keen to see that synopsis.

 

[sbrothy]

Nobel gases that do not really really react with anything, related to proteins?
Be keen to see that synopsis.

I really hope the sarcasm there was intentional.... But yes of course. I sometimes forget how smart you people on here are compared to the people I interact with on a daily basis. That came out arrogant but trust me there's a gigantic difference. In my daily life I'm a medium fish in a small pond. That's why I sometimes fall prey to the Dunning-Kruger effect on here.

I have acquaintances who can't even read and write. It's not that they are stupid but they are dyslexic and the school didn't do much back then.

EDIT: In those days if you were left-handed they forced you to use your right. Denmark has a pretty dark history regarding psychiatry. Forced lobotomies and sterilization... dark stuff. We are indeed a happy country.

 

[pinball1970]

I really hope the sarcasm there was intentional.... But yes of course.

Yes I was just ribbing you a little bit, British sense of humour ;)

I sometimes forget how smart you people on here are compared to the people I interact with on a daily basis.

Woah there, I'm not on that level!

The comment was just based on some knowledge of Chemistry.

Reading through the mathematics questions and answers and the all the physics stuff still blows my mind after 9 years on the site, it is a humbling but also a rewarding experience.

 

[pinball1970]

I really hope the sarcasm there was intentional.... But yes of course. I sometimes forget how smart you people on here are compared to the people I interact with on a daily basis. That came out arrogant but trust me there's a gigantic difference. In my daily life I'm a medium fish in a small pond. That's why I sometimes fall prey to the Dunning-Kruger effect on here.

I have acquaintances who can't even read and write. It's not that they are stupid but they are dyslexic and the school didn't do much back then.

EDIT: In those days if you were left-handed they forced you to use your right. Denmark has a pretty dark history regarding psychiatry. Forced lobotomies and sterilization... dark stuff. We are indeed a happy country.

I had that in the 1970s and as as late as the early 1980s. A drum clinic of all places, I was the only left hander and the teacher said I would have learn to play right handed. I was better than the vast majority of the drummers so I decided to stay sinister.

 

[sbrothy]

I had that in the 1970s and as as late as the early 1980s. A drum clinic of all places, I was the only left hander and the teacher said I would have learn to play right handed. I was better than the vast majority of the drummers so I decided to stay sinister

You must obviously have been devil-spawn! Nothing says pure evil as being a leftie! Imagine what they must have thought about people being ambidextrous?!

 

[sbrothy]

Michael Ellis Fisher: CV and achievements

This text was supposed to be included in the book "50 years of the renormalization group, Dedicated to the Memory of Michael E. Fisher", edited by A. Aharony, O. Entin-Wohlman, D. Huse and L. Radzihovsky, World Scientific, Singapore (2024). It will be included in future printings and in the electronic version of the book.

 

[sbrothy]

Tensorial Quantum Mechanics: Back to Heisenberg and Beyond

Interesting footnote:

It is important to remark that most physicists are not interested at all in the many “interpretations” which are heatedlydebated in philosophical journals. As Maximilian Schlosshauer [38, p. 59] has recently described: “It is no secret that a shutup-and-calculate mentality pervades classrooms everywhere. How many physics students will ever hear their professor mentionthat there’s such a queer thing as different interpretations of the very theory they’re learning about? I have no representativedata to answer this question, but I suspect the percentage of such students would hardly exceed the single-digit range.”

EDIT:

Heh, I just found the official name for this kinda problem:

Newton's Flaming Laser Sword.

 

[sbrothy]

Some history:

Fusion divided: what prevented European collaboration on controlled thermonuclear fusion in 1958

I admit this one mostly intrigued me because of Sean M. Carrol. Also, I just think emergence is a cool concept.

What Emergence Can Possibly Mean

This one just kinda spoke to me intuitively:

Geometric Proof of the Irrationality of Square-Roots for Select Integers

Got all sorts of stuff going on. I'm trying to make my computer draw some fractals for nostalgia's sake but ended up wasting a lot of time on an invalid GPG server key problem. That now out of the way I'll be looking into John Baez beautiful roots as well. I have the GNU Scientific C++ API solving lots of 23th-degree polynomials but getting it on screen......

 

[pines-demon]

This page by the AIP is a good source for the history of cosmology: https://history.aip.org/exhibits/cosmology/index.htm

 

[sbrothy]

Wow, here we're really venturing into metaphysics land:

The game of metaphysics

"Metaphysics is traditionally conceived as aiming at the truth -- indeed, the most fundamental truths about the most general features of reality. Philosophical naturalists, urging that philosophical claims be grounded on science, have often assumed an eliminativist attitude towards metaphysics, consequently paying little attention to such a definition. In the more recent literature, however, naturalism has instead been taken to entail that the traditional conception of metaphysics can be accepted if and only if one is a scientific realist (and puts the right constraints on acceptable metaphysical claims). Here, we want to suggest that naturalists can, and perhaps should, pick a third option, based on a significant yet acceptable revision of the established understanding of metaphysics. More particularly, we will claim that a fictionalist approach to metaphysics is compatible with both the idea that the discipline inquires into the fundamental features of reality and naturalistic methodology; at the same time, it meshes well with both scientific realism and instrumentalism"

EDIT:

Stumbled upon this one last second:

Hard Proofs and Good Reasons

"Practicing mathematicians often assume that mathematical claims, when they are true, have good reasons to be true. Such a state of affairs is "unreasonable", in Wigner's sense, because basic results in computational complexity suggest that there are a large number of theorems that have only exponentially-long proofs, and such proofs can not serve as good reasons for the truths of what they establish. Either mathematicians are adept at encountering only the reasonable truths, or what mathematicians take to be good reasons do not always lead to equivalently good proofs. Both resolutions raise new problems: either, how it is that we come to care about the reasonable truths before we have any inkling of how they might be proved, or why there should be good reasons, beyond those of deductive proof, for the truth of mathematical statements. Taking this dilemma seriously provides a new way to make sense of the unstable ontologies found in contemporary mathematics, and new ways to understand how non-human, but intelligent, systems might found new mathematics on inhuman "alien" lemmas."

 

[sbrothy]

I stumbled across this paper on arXiv:

Nanopore DNA Sequencing Technology: A Sociological Perspective_{physics.soc-ph}

Nanopore sequencing, a next-generation sequencing technology, holds the potential to revolutionize multiple facets of life sciences, forensics, and healthcare. While previous research has focused on its technical intricacies and biomedical applications, this paper offers a unique perspective by scrutinizing the societal dimensions (ethical, legal, and social implications) of nanopore sequencing. Employing the lenses of Diffusion and Action Network Theory, we examine the dissemination of nanopore sequencing in society as a potential consumer product, contributing to the field of the sociology of technology. We investigate the possibility of interactions between human and nonhuman actors in developing nanopore technology to analyse how various stakeholders, such as companies, regulators, and researchers, shape the trajectory of the growth of nanopore sequencing. This work offers insights into the social construction of nanopore sequencing, shedding light on the actors, power dynamics, and socio-technical networks that shape its adoption and societal impact. Understanding the sociological dimensions of this transformative technology is vital for responsible development, equitable distribution, and inclusive integration into diverse societal contexts.

I'll admit it was sheer coincidence and that my knowlegde of this particuar subject is practically nil. It does however scare me that the specific topic has apparently matured to the point where it's sociological ramifications seem worth discussing.

I realize YMMV with reagrds to "matured", "sociological ramifications" and "discussing". They may in fact vary a lot!

Using Wikipedia - which I know we don't do here - as a simple timeline it also looks like this technology is coming of age right about now. Not suprisingly boosted by the Corona Pandemic.

I've tried looking around at Preprint Server for Health Sciences and Preprint Server for Biology but having a hard time gauging the validity (harder even than I have on arXiv, where I'm a far cry for being any sort of expert).

 

[BillTre]

Nanopore sequencing has these different effects in society etc. I am guessing its involvement and use in health issues and processes isthe basis of the sociological/ethical issues . It has long been the NIH's goal to make medicine more molecular and sequence based. This is the basis of their drive to individualized medicine. The ideal would be a genome sequence of every patient.
These are developing things.
Another medical use would be identifying pathogens (like Covid).

There are also research uses of course, but these probably don't fall into the bucket of sociological impacts being considered.

 

[sbrothy]

I'm obviously been neglecting a lot of medical science, so that when some of the new stuff creeps up on me it has a tendency to freak me out!

Whether it should I'm not altogether sure though. It's not that old pictures from the ancient movie "The Fly" pops up in my head, but I must admit I feel kind of old sometimes.

 

[BillTre]

but I must admit I feel kind of old sometimes.

Getting older every day.

 

[Hornbein]

Stumbled upon this one last second:

Hard Proofs and Good Reasons

"Practicing mathematicians often assume that mathematical claims, when they are true, have good reasons to be true. Such a state of affairs is "unreasonable", in Wigner's sense, because basic results in computational complexity suggest that there are a large number of theorems that have only exponentially-long proofs, and such proofs can not serve as good reasons for the truths of what they establish. Either mathematicians are adept at encountering only the reasonable truths, or what mathematicians take to be good reasons do not always lead to equivalently good proofs. Both resolutions raise new problems: either, how it is that we come to care about the reasonable truths before we have any inkling of how they might be proved, or why there should be good reasons, beyond those of deductive proof, for the truth of mathematical statements. Taking this dilemma seriously provides a new way to make sense of the unstable ontologies found in contemporary mathematics, and new ways to understand how non-human, but intelligent, systems might found new mathematics on inhuman "alien" lemmas."

I'm no expert but I'll say that what mathematicians are really interested in are "ideas" and insight as opposed to proving something. That is, it is hoped that a proof comes up with a new idea or technique that they can use in their own work. Mathematicians I'm told spend most of their time being "stuck", getting nowhere, hoping someone will come up with something that we get them over the hump. When it happens I'm told there is a "gold rush" of applying the new idea since getting in first is rewarded. It's nice if someone proves something in some complicated way but if it doesn't have a "new idea" then it isn't that big of a deal.

In some cases only a few -- sometimes a very few -- understand the proof. Then they may (or may not) come up with some newer simplified proof that gives insight. An example of that is Feynman diagrams and his "the particle takes every path" concept, which displaced the laborious math of Schwinger. (Yes, that's a simplification.)

An example of a proof that turned out to be not a big deal would be Hilbert's proof of the Waring Conjecture. It was complicated and didn't bring insight so it was impressive but didn't make a splash. Hilbert earned his fame elsewhere. An example of someone who was really good at insight was Alexander Grothendieck, whose category theory was widely useful and caught on bigtime. Georg Cantor came up with very simple proofs of important topics, mathematicians loved that. Kurt Goedel too.

Computerized proofs maybe began with the proof of the four color conjecture. It was nice that they proved it in this complicated way but it delivered no insight so it was a disappointment. More a relief in that whew, now we can work on something else. Lately I've heard that computers came up with a better compression algorithm. While this may not have provided much insight the result was a money saver and hence important. But this is more engineering than math.

If computers made a long complicated proof or refutation of the Riemann Hypothesis that provide no insight then I say it won't make much difference in mathematics. If someone then came up with a simpler proof that was understandable they might get the lion's share of the credit, as that is what mathematicians really want. Or if a computer comes up with a simple proof of something no one cares about, that won't mean much either.

 

[sbrothy]

I'm no expert but I'll say that what mathematicians are really interested in are "ideas" and insight as opposed to proving something. That is, it is hoped that a proof comes up with a new idea or technique that they can use in their own work. Mathematicians I'm told spend most of their time being "stuck", getting nowhere, hoping someone will come up with something that we get them over the hump. When it happens I'm told there is a "gold rush" of applying the new idea since getting in first is rewarded. It's nice if someone proves something in some complicated way but if it doesn't have a "new idea" then it isn't that big of a deal.

In some cases only a few -- sometimes a very few -- understand the proof. Then they may (or may not) come up with some newer simplified proof that gives insight. An example of that is Feynman diagrams and his "the particle takes every path" concept, which displaced the laborious math of Schwinger. (Yes, that's a simplification.)

An example of a proof that turned out to be not a big deal would be Hilbert's proof of the Waring Conjecture. It was complicated and didn't bring insight so it was impressive but didn't make a splash. Hilbert earned his fame elsewhere. An example of someone who was really good at insight was Alexander Grothendieck, whose category theory was widely useful and caught on bigtime. Georg Cantor came up with very simple proofs of important topics, mathematicians loved that. Kurt Goedel too.

Computerized proofs maybe began with the proof of the four color conjecture. It was nice that they proved it in this complicated way but it delivered no insight so it was a disappointment. More a relief in that whew, now we can work on something else. Lately I've heard that computers came up with a better compression algorithm. While this may not have provided much insight the result was a money saver and hence important. But this is more engineering than math.

If computers made a long complicated proof or refutation of the Riemann Hypothesis that provide no insight then I say it won't make much difference in mathematics. If someone then came up with a simpler proof that was understandable they might get the lion's share of the credit, as that is what mathematicians really want. Or if a computer comes up with a simple proof of something no one cares about, that won't mean much either.

I'm sure. I'd expect the ultimate goal is the kind of immortality you get by getting a technique, discipline or branch named after you. Like Riemannian geometry, Clifford algebra or an Einstein ring. Heck, perhaps even one or more constants of nature. Newton did pretty good there, at least one constant of nature and a branch of mathematics!

WIKI: Things named after scientists

Tough luck when it goes wrong and someone else gets the credit, as in the example I recently mentioned here with H.C Ørsted. Or when it's something more obscure: first time I read about the "Killing-vector" it gave me a seconds pause ;)


There's a fun one here too:

Alexander von Humboldt


Many of these people also become obsessed and sometimes the line between genius and schizophrenia is a tight walk as shown in A Beautiful Mind.

The use of computers complicates stuff too yeah. I actually thought the 4-color thingy was still a conjecture but I was thinking of the ABC-one.

I'll admit that's one reason I like the historical and philosophical parts of the hard sciences. Sadly, I'm simply not that smart. I could have closed some of the gap with education but I don't think I'd ever achieve brilliance.

I'll just be thankful I can tie my shoelaces and appreciate the beauty in the fact that creation itself might one day be understood. If not by me personally at least weird gadgets almost always fall off the science-tree.

 

[sbrothy]

Courtesy of Woit's blog I see Richard S. Hamilton and Walter Neumann passed away.

Since Woit already put various biographies and stuff together I thought it appropiate to link directly there.

 

[sbrothy]

An Astronomical Interpretation of the Nebra Sky Disc

Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars.

Older Thread: Popular Physics - The Nebra Disk.

 

[sbrothy]

In Search of Truth: In memory of Balraj Singh.

 

[sbrothy]

arXiv: History and Philosophy of Physics; Condensed Matter Disordered Systems and Neural Networks; Computer Science Machine Learning; Quantitative Biology Neurons and Cognition; Other Quantitative Biology. History, reflection on Hopfield's work.

Moving boundaries: An appreciation of John Hopfield

The 2024 Nobel Prize in Physics was awarded to John Hopfield and Geoffrey Hinton, "for foundational discoveries and inventions that enable machine learning with artificial neural networks." As noted by the Nobel committee, their work moved the boundaries of physics. This is a brief reflection on Hopfield's work, its implications for the emergence of biological physics as a part of physics, the path from his early papers to the modern revolution in artificial intelligence, and prospects for the future.