This book promised a lot to me: It was going to explain what philosophers and scientists meant by "nothing". I've already read the book..."A Universe from nothing" by Lawrence Krauss...and I also watched him defending his thesis on TV. But strangely found it rather unconvincing. He seemed to want it several ways; a universe where there was a vacuum into which could pop at any moment, matter in the form of particles and the particles could disappear also. His critics were arguing that even if there were no particles and no electromagnetic waves ...then there was still something there.
JO Weatherall, in the book I'm reviewing goes into a lot more detail. And, for me, it is a lot clearer. I was fascinated for example by his suggestion about a "space" that had two waves ...each exactly cancelling out the other so that the result was no wave, and nothing to measure. But was it true to claim that the space contained nothing? Probably not.
On p 124 he summarises his main line of reasoning. How with Newtonian Physics a world of nothing would consist in empty space and time. ....It's simply a container waiting for stuff to be introduced.
In General Relativity, a world with nothing would again be a universe of space time with no matter present in any location. But the geometry of space time is rich and dynamic and allows for purely geometric phenomena that have all the hallmarks of "stuff". Like blackholes that effect nearby observers in spacecraft or gravitational waves that set springs vibrating. (Though one has to ask the question if the universe has nothing then where did the spring come from?).
Maxwell's equations raised significant questions about electromagnetic radiation. Does it count as a kind of "Stuff". It must in general relativity since it contributes to the curvature of the space time in the same way as does the sun. Then a region that is empty except for light (say) is not empty at all. He raises the question : Is light the stuff or is light just a particular pattern in a field that, like the aether, pervades the entire universe, whether it is vibrating or not?
And when we move to a quantum field theory....a state of affairs with "nothing" in the universe is represented by the vacuum state. But this sort of universe does not have the properties that we might expect of a universe with nothing in it. It seems to correspond with a situation where there are no excitations in the electromagnetic field but where there is, nonetheless, an entity (the field) present. And this can give rise to observable phenomena such as vacuum polarisation. (Some ways of understanding this are vacuum fluctuations, electron/position creation and annihilation...and all sorts of bizarre outcomes.
He makes the point that our ordinary understanding of "nothing" is not identical to these notions of the physicists....because ordinary language has been hijacked and put to work for a purpose to which it doesn't really correspond.
Perhaps the most extreme case is that of the vacuum in quantum field theory. There "something' and "nothing" are not even mutually exclusive. It is entirely consistent for there to be nothing yet for stuff to show up when we try to detect it.
Weatherall concludes that these sort of answers about "something" are probably not very satisfying. We probably didn't mean "vacuum fluctuations" when we thought of "something". Ok but what did we mean by "something"? presumably we had some impact theory of what the world would have been like if there had been nothing....and conversely.....what kind of things count as "stuff". So the ways in which the word "nothing"has been coopted by Physics does not conform with our prior intuitions. But then if our prior intuitions relay on some sort of theory...is this theory as well supported as quantum field theory and general relativity.
"Nothing"in general relativity has a completely different meaning to "nothing" in quantum field theory...and there is reason to suppose that both senses of nothing will be left behind in future physical theories .
There is a nice throwaway line that today, following Born, physicists believe that Schrodinger's waves do not describe matter directly but describe states of affairs. The wavelike properties of matter arise because the probabilities, associated with their states, oscillate.
Towards the end of the book Weatherall acknowledges that there are significant differences and incompatibilities between general relativity and quantum field theory and comments that making these two very different theories "play nicely together" is one of the most difficult and important questions facing modern physics,.....and has been so for more than four decades. He then meanders into string theory .......seemingly favouring it as a theory with possibilities .....even though string theories allow for 10 to the power of 500 different ways for there to be nothing. (As Feyman said ...string theory has to be excused most of the time....It doesn't look right.)
On the whole a really interesting book. helped explain some things to me. (Especially the terminology...."nothing" has different meanings to different physical theories....and is not the same as normal usage of the word "nothing").
But, on the other hand, I'm still left with a vague feeling of dissatisfaction that he hasn't explained all. And maybe that is because...we just don't know. At least not yet. ( )

Void: The Strange Physics of Nothing by James Owen Weatherall is a historical look at physics and vacua. Weatherall is a physicist, philosopher, and mathematician. He holds graduate degrees from Harvard, the Stevens Institute of Technology, and the University of California, Irvine, where is presently an assistant professor of logic and philosophy of science.


Weatherall takes the reader through the history of physics and in particular empty space. Throughout most of history, plenum or aether was thought to occupy the "vacuum of space". Newton believed there needed to be medium for gravity to interact through. Leibniz, a contemporary and competitor, believed empty space was possible, but he believed God kept it hidden. If man added something to empty space, he would improve on God's creation and that was not possible. It is interesting how religion still played a key role in the cutting-edge science of the time. Newton, however, was no better with his involvement in alchemy, even to the point of mercury poisoning. It is interesting to see what was mixed into science and mathematics and still succeeded.


Void ,next, takes us in the era of relativity and the end of the era of aether. With the curving of space-time, the interaction of gravity could operate through a void. Perhaps the most interesting point is defining empty space. Quantum mechanics picks up after relativity and adds an interesting and very unexpected twist to a vacuum. In addition to radiation-- radio waves and light --through a void, particles could pop in and out of existence randomly. Finally, string theory, not to be outdone, offers 10,500 possibilities to have an empty vacuum in as many universes.


Weatherall presents an interesting study on the history of science. The book reads more like a history study than a science book. This helps in making it easy to read and easy to hold the interest of a non-scientist brain. The conflict between scientists was serious, and failure was devastating to more than a few scientists. The Newton- Leibniz conflict was very bitter. Jordan and Dirac, in competition for an electron theory, was not bitter, but after Dirac’s released his equation, Jordan fell into depression and left physics altogether. The work becomes a quest for some and a place of defense for others. As each new theory makes an appearance the “old guard” is resistant. They have put their entire lives behind their theory, and to be wrong after a lifetime, is devastating.


Void is a worthwhile read for those interested in science, history, or even biography. It was a bit light on the title word but rich in background. It is a book that will make the reader think. I was fairly familiar with the history and science, in layman’s terms, and I still walked away with something. The point that the String Theory offered, in particular, that there are 10,500 universes, many of which we cannot exist in. Perhaps we are not the one in almost an infinite number of chances of existing in a Goldilocks Universe, but rather we exist in one of many possible universes where life is possible-- almost a complete reversal of the odds. My thinking is more amateur and philosophical than scientific but the idea of science is to promote the search for truth and to make one think. A well-written and extremely well-documented science (or history) book for the general public. ( )

This book promised a lot to me: It was going to explain what philosophers and scientists meant by "nothing". I've already read the book..."A Universe from nothing" by Lawrence Krauss...and I also watched him defending his thesis on TV. But strangely found it rather unconvincing. He seemed to want it several ways; a universe where there was a vacuum into which could pop at any moment, matter in the form of particles and the particles could disappear also. His critics were arguing that even if there were no particles and no electromagnetic waves ...then there was still something there.
JO Weatherall, in the book I'm reviewing goes into a lot more detail. And, for me, it is a lot clearer. I was fascinated for example by his suggestion about a "space" that had two waves ...each exactly cancelling out the other so that the result was no wave, and nothing to measure. But was it true to claim that the space contained nothing? Probably not.
On p 124 he summarises his main line of reasoning. How with Newtonian Physics a world of nothing would consist in empty space and time. ....It's simply a container waiting for stuff to be introduced.
In General Relativity, a world with nothing would again be a universe of space time with no matter present in any location. But the geometry of space time is rich and dynamic and allows for purely geometric phenomena that have all the hallmarks of "stuff". Like blackholes that effect nearby observers in spacecraft or gravitational waves that set springs vibrating. (Though one has to ask the question if the universe has nothing then where did the spring come from?).
Maxwell's equations raised significant questions about electromagnetic radiation. Does it count as a kind of "Stuff". It must in general relativity since it contributes to the curvature of the space time in the same way as does the sun. Then a region that is empty except for light (say) is not empty at all. He raises the question : Is light the stuff or is light just a particular pattern in a field that, like the aether, pervades the entire universe, whether it is vibrating or not?
And when we move to a quantum field theory....a state of affairs with "nothing" in the universe is represented by the vacuum state. But this sort of universe does not have the properties that we might expect of a universe with nothing in it. It seems to correspond with a situation where there are no excitations in the electromagnetic field but where there is, nonetheless, an entity (the field) present. And this can give rise to observable phenomena such as vacuum polarisation. (Some ways of understanding this are vacuum fluctuations, electron/position creation and annihilation...and all sorts of bizarre outcomes.
He makes the point that our ordinary understanding of "nothing" is not identical to these notions of the physicists....because ordinary language has been hijacked and put to work for a purpose to which it doesn't really correspond.
Perhaps the most extreme case is that of the vacuum in quantum field theory. There "something' and "nothing" are not even mutually exclusive. It is entirely consistent for there to be nothing yet for stuff to show up when we try to detect it.
Weatherall concludes that these sort of answers about "something" are probably not very satisfying. We probably didn't mean "vacuum fluctuations" when we thought of "something". Ok but what did we mean by "something"? presumably we had some impact theory of what the world would have been like if there had been nothing....and conversely.....what kind of things count as "stuff". So the ways in which the word "nothing"has been coopted by Physics does not conform with our prior intuitions. But then if our prior intuitions relay on some sort of theory...is this theory as well supported as quantum field theory and general relativity.
"Nothing"in general relativity has a completely different meaning to "nothing" in quantum field theory...and there is reason to suppose that both senses of nothing will be left behind in future physical theories .
There is a nice throwaway line that today, following Born, physicists believe that Schrodinger's waves do not describe matter directly but describe states of affairs. The wavelike properties of matter arise because the probabilities, associated with their states, oscillate.
Towards the end of the book Weatherall acknowledges that there are significant differences and incompatibilities between general relativity and quantum field theory and comments that making these two very different theories "play nicely together" is one of the most difficult and important questions facing modern physics,.....and has been so for more than four decades. He then meanders into string theory .......seemingly favouring it as a theory with possibilities .....even though string theories allow for 10 to the power of 500 different ways for there to be nothing. (As Feyman said ...string theory has to be excused most of the time....It doesn't look right.)
On the whole a really interesting book. helped explain some things to me. (Especially the terminology...."nothing" has different meanings to different physical theories....and is not the same as normal usage of the word "nothing").
But, on the other hand, I'm still left with a vague feeling of dissatisfaction that he hasn't explained all. And maybe that is because...we just don't know. At least not yet. ( )

Una volta era facile parlare del nulla. Beh, no: una volta non si pensava che potesse esserci "il nulla", proprio come non aveva senso parlare del numero zero. Ancora Cartesio non ammetteva l'esistenza del vuoto, e se ci pensate l'etere serviva allo stesso scopo nella meccanica newtoniana, la prima delle teorie fisiche trattate in questo libro; le altre sono l'elettromagnetismo classico, la relatività generale e la meccanica quantistica. Più che al significato fisico del concetto di vuoto (o se preferite del nulla), però, a Weatherall interessa mostrare le sue implicazioni filosofiche; s interessante la lettura che lui fa della diatriba tra Leibniz - che sicuramente il calcolo infinitesimale lo vedeva anche filosoficamente - e Newton, che oggettivamente io credevo meno interessato a tali speculazioni; sicuramente peculiari sono poi le sue interpretazioni della fisica quantistica - ma anche lì possiamo dire che ogni fisico ha le sue idee. Quello che si scopre è che il vuoto è diventato man mano sempre più "pieno", nel senso di avere una certa struttura (o tante possibili strutture come nel caso delle equazioni della relatività, per non parlare della meccanica quantistica). Nel complesso un bel testo anche se non semplicissimo, aiutato dalla buona traduzione di Andrea Migliori. ( )

Weatherall, a philosopher very well versed in physics, non-mathematically describes and contrasts the kinds of vacuum posited in Newtonian theory, relativity, and quantum field theory. At the end, he mentions that string theory may specify 10^500 vacuum varieties. The main text is not that long but heavily references the ample endnotes, which in turn heavily reference a very large bibliography.