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The Meaning of Relativity

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In 1921, five years after the appearance of his comprehensive paper on general relativity and twelve years before he left Europe permanently to join the Institute for Advanced Study, Albert Einstein visited Princeton University, where he delivered the Stafford Little Lectures for that year. These four lectures constituted an overview of his then-controversial theory of relativity. Princeton University Press made the lectures available under the title The Meaning of Relativity, the first book by Einstein to be produced by an American publisher. As subsequent editions were brought out by the Press, Einstein included new material amplifying the theory. A revised version of the appendix Relativistic Theory of the Non-Symmetric Field, added to the posthumous edition of 1956, was Einstein's last scientific paper.

-- "Physics Today"

166 pages, Paperback

First published January 1, 1922

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About the author

Albert Einstein

825 books9,230 followers
Special and general theories of relativity of German-born American theoretical physicist Albert Einstein revolutionized modern thought on the nature of space and time and formed a base for the exploitation of atomic energy; he won a Nobel Prize of 1921 for his explanation of the photoelectric effect.

His paper of 1905 formed the basis of electronics. His first paper, also published in 1905, changed the world.
He completed his Philosophiae Doctor at the University of Zurich before 1909.

Einstein, a pacifist during World War I, stayed a firm proponent of social justice and responsibility.

Einstein thought that Newtonion mechanics no longer enough reconciled the laws of classical mechanics with those of the electromagnetic field. This thought led to the development. He recognized, however, that he ably also extended the principle to gravitational fields and with his subsequent theory of gravitation in 1916 published a paper. He continued to deal with problems of statistical mechanics and quantum theory, which led to his explanations of particle theory and the motion of molecules. He also investigated the thermal properties of light, which laid the foundation of the photon.

Best known for his mass–energy equivalence formula E = mc2, dubbed "the world's most famous equation," he received "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect". The latter was pivotal in establishing quantum theory.

He visited the United States when Adolf Hitler came to power in 1933 and went not back to Germany. On the eve of World War II, he endorsed a letter, alerting Franklin Delano Roosevelt, president, to the potential development of "extremely powerful bombs of a new type" and recommending that the United States begin similar research. This recommendation eventually led to the Manhattan project. Einstein supported defending the Allied forces but largely denounced the idea of using the newly discovered nuclear fission as a weapon. Later, with Bertrand Russell–Einstein manifesto highlighted the danger of nuclear weapons.

After the rise of the Nazi party, Einstein made Princeton his permanent home as a citizen of United States in 1940. He chaired the emergency committee of atomic scientists, which organized to alert the public to the dangers of warfare.

At a symposium, he advised:
"In their struggle for the ethical good, teachers of religion must have the stature to give up the doctrine of a personal God, that is, give up that source of fear and hope which in the past placed such vast power in the hands of priests. In their labors they will have to avail themselves of those forces which are capable of cultivating the Good, the True, and the Beautiful in humanity itself. This is, to be sure a more difficult but an incomparably more worthy task... "

("Science, Philosophy and Religion, A Symposium," published by the Conference on Science, Philosophy and Religion in their Relation to the Democratic Way of Life, Inc., New York, 1941).

In a letter to philosopher Eric Gutkind, dated 3 January 1954, Einstein stated:
"The word god is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable, but still primitive legends which are nevertheless pretty childish. No interpretation no matter how subtle can (for me) change this."

(The Guardian, "Childish superstition: Einstein's letter makes view of religion relatively clear," by James Randerson, May 13, 2008)

Great intellectual achievements and originality made the word "Einstein" synonymous with genius.

The institute for advanced study in Princeton, New Jersey, affiliated Einstein until his death in 1955.

More: http://en.wikipedia.org/wiki/Albert_E...


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Displaying 1 - 30 of 35 reviews
Profile Image for Manny.
Author 30 books14k followers
March 8, 2013
I will say at once that there was a great deal I did not understand in this book, which is based on four lectures Einstein gave at Princeton in 1921. Though short, it is very dense, and obviously written for people who know considerably more physics and mathematics than I do. But I had read enough about the content elsewhere to be able to follow the general outlines of the argument, and I will do my best to explain what I got out of it.

Einstein's main goal is to show you how he arrived at the Theory of General Relativity. The basic idea is extraordinarily simple and logical: he wants to formulate the laws of nature in a way that is independent of the coordinate system chosen. This may sound modest, but it is not. In case you are in doubt, he invites you to consider the case of a rotating object like the Earth. In Newtonian physics, you have to use an "inertial" frame of reference, motionless or moving uniformly with respect to the fixed stars; then you can explain things like Foucault's pendulum.

But Einstein wants it also to be possible to adopt the Ptolemaic frame of reference, where the Earth stands still and the rest of the universe rotates around it. For Galileo and Newton, this would have made no sense at all, since space for them was absolute. Einstein shows that his great predecessors were wrong: you can have a consistent picture where these shifts are mathematically meaningful. If the Earth is standing still and the universe is rotating, the rotating gravitational field created by the distant stars will drag Foucalt's pendulum along with it. You need to identify gravity and acceleration, and model them both as curvature of space-time. It turns out (though the details are very complicated, and I couldn't follow them), that there is just one straightforward way to organize the scheme. This turns out to be the central tensor equation of General Relativity.

Having made this incredible discovery, you'd think Einstein would have been happy, but he wasn't. He felt he'd left things at best half-completed. His theory predicted singularities in what we would now call black holes (Einstein never believed in black holes, and hated them), and it had no elegant explanation for electromagnetic forces; they were just pasted on in an ugly and unsatisfying fashion. Einstein famously spent the second half of life in a fruitless search for a solution, and his frustration shines through. It is interesting to see how ruthless he is about discarding approaches which don't feel right. String theory wasn't even on the horizon yet, but this passage is remarkably prescient and I'm surprised I haven't see it quoted before:
More complex field theories have frequently been proposed. They may be classified according to the following characteristic features:

a) Increase of the number of dimensions of the continuum. In this case one must explain why the continuum is apparently restricted to four dimensions.

b) Introduction of fields of different kind (e.g. a vector field) in addition to the displacement field and its correlated tensor field gᵢⱼ.

c) Introduction of field equations of higher order (of differentiation)

In my view, such more complicated systems should be considered only if there are physical-empirical reasons to do so.
I would have loved to watch him debate Susskind or Polchinski.

Einstein, Einstein, Einstein. Even if I only grasp a tenth of what you're telling me, you rock are an extraordinary person. I'm sorry you didn't wrap it all up the way you wanted to, but, you know, still pretty good for a mortal man.
Profile Image for E. G..
1,112 reviews684 followers
March 6, 2017
A Note on the Sixth Edition

--The Meaning of Relativity

Appendix I: On the 'Cosmologic Problem'
Appendix II: Relativistic Theory of the Non-symmetric Field

Profile Image for Laura.
6,909 reviews565 followers
February 26, 2023
Free download available at Project Gutenberg

I do recommend this book for those people (especially scholars) who are interested to understand the principles of Einstein´s theory of relativity.

I made the html5&svg images version of this book for Free Literature and Project Gutenberg will publish it.
Profile Image for Kerem Cankocak.
78 reviews55 followers
March 28, 2016
Albert Einstein genel görelilik konusundaki kapsamlı makalesinin yayımlanmasından beş yıl sonra, 1921 yılında, görelilik kuramının daha kesin şekilde onay görebilmesine giden yolu sağlamlaştırma amacıyla misafir profesör olarak Princeton Üniversitesi'ne gitti. Burada verdiği dört ders Göreliliğin Anlamı başlığıyla yayımlandı ve Einstein'ın ölümüne dek her basımda gözden geçirildi.

Einstein'ın verdiği örnekler ve algıladığı göreli dünyanın tanımları oldukça açıktır, izlemesi de kolaydır. Ancak sunumu, bilimle ilgisi olmayan okuyucular için matematiksel bir derinlik içermektedir ve bu da anlatımdaki akışın yavaşlamasına yol açabilir. Matematikle ya da bilimle ilgisi olanlar için ise bu dersler son derece aydınlatıcı olacaktır. Bu kitap Einstein'ın bir "ders kitabı" yazmaya en çok yaklaştığı örnektir. Göreliliğin Anlamı, konu hakkında bugün artık iyi bilinen yaklaşımların çoğuna öncülük yapmaya ek olarak, sonradan başka araştırmacılar tarafından yeniden keşfedilen birçok düşünceyi de içermektedir.

"Einstein'ın görelilik kuramları büyük bir kuramsal sentez örneğidir. Eğer bu kuramlar olmasaydı hiç şüphesiz günümüzdeki fizikçiler farklı mecralara sapacaklardı. Einstein fizikte birleşik kuramlar için meşaleyi yakmıştır. Bizler bu meşaleyi yanık tutmaya devam ediyoruz."
-Brian Greene, Evrenin Zarafetinin yazarı-

"Göreliliğin Anlamı gelişme aşamasındaki bir devrimi belgelemekte ve dikkatli okuyucuya bu alanda başka fizik kitaplarında bulunandan daha derin gerçekler sunmaktadır."
- Physics Today-
Profile Image for Salma Bahaa.
23 reviews2 followers
July 9, 2016
Was it a good book? Yes it was. Did I enjoy it? Yes, yes I did. Did I understand a tenth of it? BUAHAHA. No.
Well, I did understand a good deal, compared to the knowledge I already had about the complex theories and lectures discussed in the book. I actually found some satisfying answers to question that itched my mind for some time. However, even though this book did benefit me, I believe that it is more beneficial to those who are more knowledgeable about mathematics and physics than I am, as they would be able to get the most out of it. But even if you are not that much of a math person or a physics prodigy, you should read it.
Why you should read it: Einstein said his goal with the book was to give an insight into the theory of relativity to interested non-experts. This work does exactly that: “Nobody is better at explaining relativity than Einstein himself; his account provides a combination of depth and clarity that only he could confidently produce,” writes Tom Siegfried of Science News.

Profile Image for Roberto Rigolin F Lopes.
363 reviews98 followers
January 5, 2019
We are in 1922, Einstein is explaining relativity for experts. He assumes that you know classical physics and don't bother explaining notations for Newton’s laws and Maxwell’s equations (this book is short). Here goes some impressions from a layperson. He deliberately challenges the idea of space and time being slowly developed over centuries as fixed references to any event. You can't be more rebel than that. And goes about laying down his theory (this lecture happened more than 10 years after his paper so he also shares developments/experiments from other scientists). There are plenty of equations in this book, many with partial derivatives in a four-dimensions universe replacing Newton’s algebraic relations. Reality is a bit more complicated after Einstein but nowadays relativity is addressed in high school books (another day I skimmed a Physics book for teenagers in Germany).
Profile Image for Nathan Albright.
4,488 reviews110 followers
September 14, 2017
It's a good thing this book has an introduction, because this particular work presents a bit of a conundrum for many readers, myself included.  This short book, which including two appendices of some length comes out to only a bit more than 150 pages in length of Einstein's material, finds itself in a bit of an uncanny valley as a work, but this is not necessarily a bad thing [1].  Einstein, like a few of the great theoretical scientists of our time (Hawking comes to mind here), seeks to write in such a way that he can be understood by a wide audience, but this book is exceptionally technical and requires a great deal of familiarity with mathematics in order to understand.  For example, it would be hard to get through much of this book sober if you played a drinking game that required drinking a shot every time that the word "tensor" was mentioned.  That aside, though, this book is to be praised for the effort of its author in making the mathematics of special and general relativity accessible to a wide audience, even if this is a difficult book to understand.  For those who are willing to take on the challenge of reading this book, though, there are some immensely useful lessons that can be gathered from Einstein's approach.

In terms of its contents, this book is organized in a very straightforward and direct fashion, not wasting paper or the time of the reader, which is something to be appreciated.  The introduction to the work provides the context of the work in discussing the problem that many people have in getting an intuitive feel for the world of relativity. After this the author discusses a look at space and time in pre-relativity physics, looking at what was thought to be constant.   The author then looks at the theory of special relativity, spends a bit more time on the general theory of relativity in two chapters, and then writes two appendices that discuss some notes for the second edition as well as providing a rigorously mathematical relativistic theory for non-symmetric fields.  One of the striking aspects of this book, aside from its sheer number of mathematical equations and the fact that the author seems to think that understanding what he is writing is a trivial and easy task, which is not the case, is the way that Einstein strives to work on setting boundary conditions and define as broadly as possible.

This is a notable trait that is worth pondering not just for theoretical physics but also in other areas of life.  Much of the difficulty in understanding relativity and its implications is the fact that people tend not to be able to imagine very well, and theoretical physics definitely requires imagination in order to visualize.  In reading this book it is clear that Einstein was able to live in a world governed by the Maxwell-Morey equations long before others did so, and his realization of their implications for classical physics gave him an advantage when it came to envisioning and describing and justifying a radically different conception of the world than the world of Newtonian physics that most of us tend to live and breathe in regardless of our knowledge of the physics developments of the last century or so.  It is also clear that Einstein spent a lot of time trying to ponder the implications of his own work and make it as generally applicable as possible, while also reminding readers that without a constant one cannot make sense of a universe.  That truth is an important one to remember, and it is unfortunately something that those who have misapplied relativity into relativism all too frequently forget.

[1] See, for example:



Profile Image for Margaret Langstaff.
Author 13 books57 followers
August 3, 2016
Whammo! The man who couldn't get a teaching job, whom everyone who knew thought a hopeless nutcase, and a virtual nobody at the time in the world of scientific research, this man wrote a paper in the dim light of early 20th century, The Special Theory of Relativity, and changed our conception of the physical universe and our physical world forever. His subsequent research in physics continued and built upon the findings in this book (independently proven by others as accurate)and the rest is history: His metamorphosis in the public eye into a genuine genius and research that built upon his findings resulting in jaw-dropping human acts of both destruction (nuclear warfare) and discovery that made our world a better place for life (advances in science and medicine from space exploration). No one knows what's next, but the works of his contained in this book were seminal and its seeds continue to sprout and grow every day, for good and ill.
262 reviews3 followers
February 3, 2019
What a great book for this time of life! I now understand
1. That Maxwell's equations force special relativity--time dilation, etc.
2. Once you have gravity present in these systems, space must be curved in order for all the physics we know to work (transform in different reference frames). General relativity only shows up with velocities near the speed of light.
3. The equations generated in general relativity are not fixed (e.g. the curvature of space) but depend upon the value of a constant called, amazingly enough, the cosmological constant. The cosmological constant is still not known.
4. For some reason, Einstein and others want a field theory for gravitation--this part of the book I did not understand at all (hence 4 stars instead of 5 stars).

Only took me 6 months to read this book.

I bought this book from the University of Chicago bookstore on Nov 29, 1976 for $2.95 plus $0.15 tax according to a receipt in the book. Maybe it took me 40+ years to read this book.
Profile Image for Eric Amidi.
Author 1 book1 follower
September 25, 2016
The way that Tensors are explained in this book is very old-fashioned, and understandably so. Today, you can learn it in a more advanced and intuitive way. However, this book affected me when I first read it many years ago. The way it affected me was that it introduced me to Einstein's way of thinking. As you go through the book, you learn about Einstein's thought process. You learn how he would base his theories on logical thinking instead of common beliefs at the time. That way of thinking impacted me a lot at an early age. What I learned from it was that the right way of thinking and problem-solving is using logic plus Occam's Razor i.e. simplicity.
Profile Image for Ahmad.
3 reviews
November 16, 2009
when the time is not absolute it is so difficult to imagine such univers.i believe relativity theory is the begining of a new way of undrestanding of the world by mixing of experiences and deep imagination.
Profile Image for Andreea.
189 reviews113 followers
December 31, 2012
"Teoria relativitatii pe intelesul tuturor" (titlul real) - close enough...

Nu e chiar pe intelesul tuturor (cei ca mine, care habar n-au de fizica), dar explica destul de detaliat asa incat, daca te chinui (si citesti de mai multe ori), vei intelege.
Profile Image for Joyce F.
34 reviews2 followers
June 1, 2009
I am not a scientist, but I was curious and this book really helped. I highly recommend it. Also ... a good idea to read this or another like it before picking up quantum theory/mechanics texts.
1 review
May 4, 2012
The paperback versions of this book are great. The Sony eReader edition is missing more than 70% of the actual equations and the rest are filled with typos so don't buy this book at Sony!
104 reviews7 followers
July 17, 2014
More difficult to penetrate than Relativity: The Special and the General Theory, which is written for a lay audience anyways. However, an excellent companion to that book (which I now own).
Author 3 books12 followers
November 18, 2014
Some insights but you need advanced mathematics to read this one and get the most out of it. Some great commentary by Einstein as he explains the theory.
Profile Image for Akinbo Ojo.
Author 1 book
July 11, 2016
A necessary reference item in the personal library for all interested in theoretical physics.
40 reviews
January 17, 2017
Needs a great deal of background in vector calculus, electromagnetism and differential equations.
Profile Image for PuchoAlmighty666.
36 reviews8 followers
August 12, 2018
I'm not a fan of Mathematics. So this book was both interesting and boring for me to read. I kinda had a hard time getting through with it.
Profile Image for Cait Koffarnus.
245 reviews1 follower
April 3, 2019
If this is the layman’s introduction to the theory of relativity, then I need the children’s version.
Profile Image for Rudro.
8 reviews
April 12, 2019
Well written but if you don’t like math then skip this book cause it's full of equations.
Profile Image for Pi.
981 reviews18 followers
November 19, 2021
Mam taką półkę z książkami, które ratują życie. Są to pozycje, dzięki którym całkowicie odcinam się od świata zewnętrznego, od codziennych, żałosnych problemów i problemików, od doniesień medialnych pełnych fałszu, prowokacji i próby zrobienia nam wody z mózgu, a najlepiej, by z mózgu nawet wody nie było - by mózgu odbiorca po porostu nie posiadał. Są to książki, które sprawiają, że bełkot celebrytów, ich absolutnie niemierzalna głupota i wstrętny egoizm odchodzą w cień, gasną a w zamian pojawia się piękne światło nauk ścisłych, trudnej drogi do prawdy - ale drogi, którą nie tylko warto podjąć, ale i trzeba, bo tak jak prawda jest jedna, tak i jedna jest słuszna droga. I tak właśnie jest z (można już rzec - KLASYKĄ) ISTOTĄ TEORII WZGLĘDNOŚCI genialnego umysłu Alberta Einsteina.
Nie będę tu się chwalić, że wszystko pojęłam, ale pochwalę się, że próbuję. Wykradam z czasu (o ironio) cenne chwile i poświęcam je na stuprocentowe skupienie. O tak! STUPROCENTOWE! Mniejsze tutaj zawsze będzie za małe, by zbliżyć się do celu. Pełna koncentracja, odcięcie się od szumu informacyjnego atakującego mój mózg z każdej szczeliny (o ironia) przestrzeni.
CZAS i PRZESTRZEŃ, czyli pierwsze, o czym mistrz nam opowiada i pierwsze, co nam burzy. Ten spokojny obraz poukładanego świata zgodnego z cykaniem zegarka. Zrozumieć znaczy doświadczyć szczęścia. Ta chwila, w której czytasz setny raz, to samo i za sto pierwszym krzyczysz EUREKA! Szczęście nie do opisana, radość, że coś wiesz - NAPRAWDĘ.
U mnie to jest tak, że moment zrozumienia staje się punktem, po którym następuje euforia, a po niej dalsze pytania... i ponowne niezrozumienie. Ciągłe szukanie. ISTOTA TEORII WZGLĘDNOŚCI będzie czytana i czytana, bo ja też i nie jestem fizykiem, matematykiem, ani innym Einsteinem... jestem taką o - myszką - która lubi wpaść w świat doświadczalny, w świat pewny, choć nadal szukający, ale szukający nie ideologii, ale odpowiedzi.
To wznowienie jest o tyle świetne, że dysponuje WSTĘPEM Briana Greene'a, którego "Piękno Wszechświata" pokochałam... ale totalnie zawiodłam się na jego innej pozycji "Do końca czasu" (ideologiczny bełkot). Mimo jednego zawodu, pozostał wciąż zachwyt, bo uwielbiam jego jasne, precyzyjne tłumaczenie trudnych zagadnień ze świata nauk ścisłych, kosmologii, astrofizyki. Ten WSTĘP jest świetnym wejściem w świat Einsteina, a i ofiaruje czytelnikowi sprytne podszczypnięcie w postaci nawiązania do teorii superstrun, którą to Greene zajmuje się z pasją.
Rewelacyjnie wydana (okładka to mistrzostwo), z fantastycznym WSTĘPEM i ARCYDZIEŁEM nauki jakim jest TEORIA WZGLĘDNOŚCI i to, co z niej wynika - KSIĄŻKA, którą warto mieć! Dajcie się namówić na tę intelektualną rozgrywkę, na tę podstawę naszego bytowania, na tę kosmiczną grę, w którą gramy wszyscy z nominacji urodzenia... grajmy w nią więc mądrze, poznajmy jej zasady.

arcydzieło geniusza otwiera drzwi zrozumienia
Wydawnictwo Zysk i S-ka
Profile Image for TheTomCZ.
2 reviews
February 5, 2022
This is not a book for a casual reader. Not even a book for a science fan. Not for an advanced science enthusiast. You need to have at least an university degree from mathematics and/or physics to understand and appreciate these lectures. And I'm not exaggerating. Another thing to mention is this lecture is given by young Albert Einstein, before he got so good at explaining this theory to masses, and before a lot of relativity's impacts were realized. So, if you just wanna learn something about this topic, more modern popular authors may be a better source (Greene, Hawking), and if you really insist on learning from the author himself, at least get a book from older Einstein, like The Evolution of Physics. If you deal daily in theorems and proofs, you understand tensors and integrals, probably know a lot about relativity already and just wanna learn the exact way Einstein himself worked in this area, then and only then is this a book for you.
Profile Image for Timothy Morrison.
843 reviews20 followers
September 4, 2022
In 1921, five years after the appearance of his comprehensive paper on general relativity and twelve years before he left Europe permanently to join the Institute for Advanced Study, Albert Einstein visited Princeton University, where he delivered the Stafford Little Lectures for that year. These four lectures constituted an overview of his then controversial theory of relativity. Summary by Goodreads
Profile Image for Tomás Martín.
21 reviews1 follower
July 13, 2023
Quizá un poco técnico para el público más general, pero una recomendación buenísima para aquel que controle un poco de lenguaje matemático y quiera entender el complejo mundo que nos rodea. No hace falta saber nada de física de antemano, pero sí estar familiarizado con conceptos matemáticos de nivel de instituto.
Profile Image for Muhammad.
73 reviews55 followers
April 6, 2022
I'm sure for a mathematician this is some brilliant stuff, but I just needed a general summary which I did not find. There doesn't seem to be a conclusion where the ideas are summed up for someone not studying to be a physicist.
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