Niels Bohr’s Times: In Physics, Philosophy, and Polity by Abraham Pais (PDF)

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The life of Niels Bohr spanned times of revolutionary change in science itself as well as its impact on society. Along with Albert Einstein, Bohr can be considered to be this century’s major driving force behind the new philosophical and mathematical descriptions of the structure of the atom and the nucleus.Abraham Pais, the acclaimed biogrpaher of Albert Einstein, here traces Bohr’s progress from his well-to-do origins in late nineteenth-century Denmark to his position at centre stage in the world political scene, particularly during the Second World War and the development of atomic weapons.Pais’ description moves through the science as it was before Bohr, as it became because of Bohr, and thence to Bohr’s scientific and philosophical legacy. That legacy is contained both in theory as it is now universally enshrined, as well as in its practice in such great Danish institutions as Riso. But more than that, Pais captures the essence of Bohr, the intensely private family figure who, despite appalling personal tragedy, became one of the most loved cultural figures of recenttimes.

User’s Reviews

Reviews from Amazon users which were colected at the time this book was published on the website:

⭐Physicist D.C. Mattis, writes: “…an important theorem in statistical mechanics by Niels Bohr in his doctoral thesis of 1911 not recognized for the significant landmark it was.” (1965, page 21, Theory of Magnetism). That theorem marked the end of classical phase of magnetism and the beginning of the quantum phase. Now, Pais does not expound on details of Bohr’s doctoral thesis, writing: “his doctor’s thesis pushed him to the outer frontier of classical physics.” (page 111). Let us read Pais:(1) If you know of Niels Bohr by way of two phrases, correspondence principle and complementarity, then you are hardly alone. Now, Pais does spend time on those aspects of Bohr at the expense of other things (which may be why Bohr is less known among the public than Heisenberg or Schrodinger). Pais: “Why is it that many members of my generation barely know that Bohr was such a significant figure ? ” (page 29). An answer (even so in my generation) is because too much philosophical obfuscation surrounds Bohr.(2) Pais does some things well, for instance: the rapid-fire surveys of the historical antecedents of modern physics (beginning chapter four and continuing chapter five). Turn these pages to Max Planck: ” I have stressed Planck’s failures rather than his progress…because his role is by no means fully revealed by the statement that in 1900 he discovered the quantum.” (page 84). If it be mysterious, I encourage the reader to read Kuhn’s detailed analysis: Blackbody Theory and the Quantum Discontinuity (1978).(3) Back to our subject, Niels Bohr: “Each one of his carefully formulated sentences revealed a long chain of underlying thoughts, of philosophical reflections, hinted at, but never fully expressed…he had reached his results not so much by calculations as by intuition and inspiration.” (page 205, words of Heisenberg).That style is indicative generally of Bohr. Pais: “It–correspondence principle–becomes nowhere clear in what technical sense it applies to atomic constitution.” and “Symmetry, used only infrequently.”(4) If you have studied Pais’ earlier book on Einstein, Subtle is the Lord, then chapter 11 is superfluous.(5) Pais mentions Bohr’s two “major contributions” to quantum theory: “discovery of selection rules” and “correspondence principle.” (page 268) writing “these selection rules illustrate…insistence on validity of classical physics as a limit of quantum physics.” A layman will be at a loss to fully appreciate that remark.(6) It is my opinion that as much as the debate between Albert Einstein and Neils Bohr is emphasized, the debate between Werner Heisenberg and Neils Bohr is as valuable (page 300). Heisenberg: “when we get beyond this range of classical theory, our words don’t fit.” (page 310). Reiterate: “our words don’t fit.”(7) Read Bohr (1928): “our interpretation of the experimental material rests essentially upon the classical concepts.” Pais writes: “One may say that with the elaboration of that statement, the logic of quantum mechanics reached its closure.” (page 313). Re-read that ! It will not make any more sense ! Again, Bohr: “an independent reality in the ordinary–that is, classical–physical sense can…neither be ascribed to the phenomena nor to the agencies of observation.” (page 314).(8) Pais: “he had good ideas about isotopes” and “he had been the first to demonstrate that beta-decay is a nuclear process.” (page 325). In 1936, of Bohr’s first communication: “…as usual, contains no equations.” (page 337) and “Bohr’s qualitative considerations of these phenomena…” (page 339). It is difficult to get a handle on exactly what it is that Bohr did (using “no equations” and “qualitative considerations.”).(9) “Bohr opted for energy non-conservation.” (page 366). Dirac, Pauli, Rutherford thought otherwise.(10) Not until I had studied Brack and Bhaduri’s ‘Semi-Classical Physics’ (1997) and Gutzwiller’s ‘Chaos in Classical and Quantum Mechanics’ (page 193) did it became clear to me what Bohr had accomplished. Pais, the discussion of Bohr and Hydrogen atom: “Bohr did not derive, but rather postulated.” (page 151).(11) Concluding: Pais’ biography of Bohr is worth exploring. Pais writes: “all history is subjective in character (page 5).” This biography is ample evidence of that, but, despite that, it remains well-written.

⭐Print too small for me to read, alas.

⭐Abraham Pais knew well both Einstein and Niels Bohr. This biography draws on his friendship with Bohr; it has many citations that were available to Pais only because of this friendship with Bohr, his wife and his family. Besides having access to many documents that other biographers might not have, the book also draws on the author’s personal experiences with Bohr. The availability and the depth of documentation along with the personal angle are the book’s strong points. In places, especially after Pais came to know Bohr, the reader gets a nice sense of Bohr as a father, husband and model for young physicists. It will be hard to find a book on Bohr now or in the future that has as much in-depth and personal insight on the man. The book will be a resource for all future work.Given all the data and personal insight, it is a shame that the book is not better written. The organization is often very poor. Topics jump back and forth between paragraphs without clear transitions at times and personal information is often mixed with equations that will turn off the reader who does not have a mathematical background in physics. Some chapters often have short paragraphs or lists that outline events but do not explain them much at all. Pais tries to solve the problem of mathematical technicality by subdividing chapters frequently and marking with an asterisk those subdivisions that might be too technical. These, the author says, can be skipped. But this fails for two reasons. First, important material about Bohr himself is often intertwined with the technical work in these sections. Second, there are several sections not marked with an asterisk that also have a great deal of technical material. Another reviewer blames the editing for the book’s unevenness. That is undoubtedly part of the problem. But part of the problem might also reside with the author who is so steeped in physics himself that he cannot understand how educated readers in other fields could fail to comprehend the mathematical work in here. He has a somewhat incredible line in the introductory “For the Reader.” Pais, quoting Bertrand Russell, says “There are several sentences in the present volume which some unusually stupid children of ten might find a little puzzling.” That seems to reflect the author’s attitude toward the reader in parts of the book. What Pais wants to do is “counteract the many cheap attempts at popularizing this subject, such as efforts by woolly masters at linking quantum physics to mysticism.” I completely agree that there is a great deal of junk about quantum physics on the market linking it to everything from consciousness to religion. But it is hardly the case that clear nonmathematical explanations in a book constitute “cheap attempts at popularizing” or that the opposite of mindless speculation about quantum physics is necessarily the style of this particular book. Blaming the reader only goes so far.The book has some real strengths. Parts are highly insightful and well-explained and the book is a gold mine for future historians on Bohr. But readers, even those that are not unusually stupid ten-year olds, may find it uneven and unnecessarily technical in sections.

⭐Pais is a beautiful writer, an admirable human being, and a fastidious chronicler of the history of physics. I confess that I loved all three books he has written. It is true that you cannot really appreciate this material if you don’t know some physics and you don’t care about the details of quantum mechanics and nuclear physics. But if you do, this is the books for you.

⭐A precious book about the way physics proceeded in XX century, higlighting the minds and human efforts which broughtto ever new understanding, while in standard physics books, the tortuous path is completed ignored, presenting only thebare exposition of theories without the link to the path they came to be so.

⭐Great book so far. I have completed about 60% of the book. Some of the theoretical sections require two or three readings before they make sense.I would recommend it to anyone interested in the history of theoretical physics.

⭐Clearly written, deeply researched, well informed, gives extensive background not only on history of science, but also on Denmark, Bohr’s family history, etc.The author had been a friend and colleague of Bohr.

⭐Terrific book about a great person.

⭐Fully, if clumsily titled Neils Bohr’s Times, in physics, philosophy, and polity, this is the definitive scientific biography of Bohr by fellow physicist Abraham Pais who knew and worked with him.The good news is that this chunky title will give you an in-depth look at Bohr and his work. From his early days in Copenhagen, through his brief but fruitful stay in the UK, his return to Denmark, the rush to safety in the Second World War and his gradual move to elder statesman of quantum physics, it’s all here.As is often the case with a biography written by another scientist, the science content is quite heavy and sometimes not the easiest to digest, but it is worth battling through, and the picture of Bohr himself that comes out of this book is second-to-none. Niels Bohr sometimes gets a rough time of it, in part because his own communication was often rather opaque, but Pais will really open your eyes to Bohr’s importance.The book dates back to 1991 but is none the worse for that. If you really want to understand the development of quantum physics in its historical and scientific context, this should be on your reading list.

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