In some New Scientist towards the end of 2005 there were interesting articles speculating with what would have happened if Newton for some reason had not published his Principia or if Einstein's 1905 papers had been rejected and Einstein had remained an unknown crackpot or .... I shall continue the speculation but first it is good to briefly summarize what happened during the last two Golden Decades of Physics we have been enjoying. Since this is not a scientific article I summarize only the discoveries without mentioning the names of those who have already visited Stockholm.
A. The real course of events
We all of course remember quite well that the revolution that began around 1983 as TGD made its breakthrough. Although the work was a mere thesis worked out during four years containing no hightech calculations, it stimulated a fantastically rapid development of ideas. In the perspective provided by these two decades it is easy to understand that the identification of space-time as a four-surface in certain higher dimensional space-time fixed completely by the standard model symmetries, happened to be a bottleneck idea which opened flood gates for cascades of new profound ideas which revolutionized the world view just like quantum mechanics had did for almost century before.
1. Physics as spinor geometry of the world of classical worlds
After a couple of years of unsuccessful attempts to quantize the theory using functional integral approach the idea about physics as the spinor geometry of the world of classical worlds was proposed. Apart from quantum jump the construction of quantum states of the Universe reduced to the construction of the modes of classical spinor fields in the "world of classical worlds" as representations of certain super-conformal algebras. Could one imagine anything simpler conceptually! Soon popped up the idea that this infinite-dimensional space could determined completely by its mere mathematical existence. The generalization of Einstein's geometrization program to infinite-dimensional context might allow only single physics! It is easy to imagine what explosive enthusiasm this raised in the brilliant minds of my brilliant colleagues.
The notion of gravitational holography emerged as a basic implication of the general coordinate invariance which implied that given 3-surface corresponds to a unique 4-surface having identification as a generalized Bohr orbit.
The microlocality at space-time level was replaced in TGD framework with purely classical locality in the world of classical worlds having 3-surfaces as its points. The basic mathematical implication was that the theory was free of those divergences of quantum field theories which were due to the space-time-local interactions. Space-time non-locality implied also the breakdown of age-old reductionistic dogma implying that theory has highly non-trivial implications in all length scales, perhaps the most interesting ones in biology. Within few years became clear that the reductionistic dogma had been perhaps the most colossal self deception that human kind had ever managed to perform.
The construction of configuration space spinors led to deep connections with von Neumann's algebras. The so called hyper-finite factors of type II1 were discovered to correspond directly to Clifford algebras for configuration space spinors. Direct connections with minimal conformal theories, quantum groups, braid groups, topological quantum computation,... emerged: these fields were developing in parallel with TGD. The most fascinating implication was a possible elimination of infinities based on the replacement of the extremely singular von Neumann algebras of quantum field theories known as factors of type III of quantum field theories with the mentioned hyper-finite factors of type II1.
At the same time came the realization that four-dimensional space-time is completely unique in the sense that light-like causal horizons at which induced metric becomes degenerate allow generalized conformal invariance. Partons could be identified as 2-dimensional sections of the causal horizons and a very close connection with conformal field theories emerged since in certain well defined sense parton physics was effectively 2-dimensional.
2. New view about space-time
Even classical theory, which had become an exact part of quantum theory, experienced a conceptual revolution. The notion of many-sheeted space-time, topological quantization of classical fields implying the notion of magnetic body which became the basic notion of TGD inspired quantum biology, the new views about the relationship between geometric and subjectively experienced time and gravitational and inertial energy, are only few items in the list of discoveries. The new views implied intense theoretical speculations about new communication technologies based on signals propagating backwards in geometric time whereas non-local energy usage was made possible by emission of negative energy signals: these mechanisms became conceptual corner stones of TGD inspired quantum biology.
Despite intense collective efforts, it took rather long time to discover the correct interpretation for the predicted classical long ranged color and weak fields seemingly in complete contradiction with experimental reality. The resolution of mystery came with the realization that the theory predicts entire fractal hierarchy of standard model physics at various sheets of many-sheeted space-time. p-Adic length scale hierarchy and hierarchy of dark matters labelled by values of Planck constant provided quantitative content for this picture. This discovery would have not been taken seriously unless already the anomalies of physics of water would have provided direct experimental support for this picture. Just as people suddenly began to see solitons and fractals everywhere for few decades earlier, subtle signatures of dark matter suddenly popped up everywhere.
3. From quantum measurement theory to a quantum theory of consciousness
The interpretational problems of quantum TGD did not leave any other possibility than extending the existing quantum measurement theory to a theory of consciousness. This in turn forced to generalize quantum theory itself: dynamical quantized Planck constant having arbitrarily large values meaning the possibility of macroscopic quantum phases even in astroscopic length scales was one the most powerful implications, and led to a rapidly growing understanding of dark matter as a hierarchy of macroscopic quantum phases characterized the value of Planck constant. Simultaneously came the realization that it is dark matter which makes living matter alive, and this launched a vigorous evolution of ideas in a new branch of science christened quantum biology.
4. Physics as a generalized number theory
A further thread in the evolution of ideas were number theoretical vision about physics which emerged gradually from an observation that elementary particle mass spectrum could be understood in terms of p-adic thermodynamics for super-conformal invariant system with Hamiltonian replaced by the generator of scaling. This approach assigned to each particle a prime characterizing its mass scale.
Later emerged the vision about physics as a generalized number theory obtained by algebraically continuing rational physics to various number fields with p-adic space-time sheets interpreted as space-time correlates of intentionality. The concept of number field was generalized by fusing real numbers and various p-adic number fields along common rationals to a larger book like structure. The notion of infinite primes emerged and the construction of infinite primes turned out to be very much analogous to a repeated quantization of an arithmetic quantum field theory. Number theoretical approach led also to a new number theoretic notion of information, with genetic code as one application of this concept.
B. Why "What if..."?
I know that most readers think that things could not have gone differently. I am however not so sure about this. After all, there was very strong opposition in my own country against TGD. There were very determined attempts to silence me completely: even after the publication of thesis I had to continue working as an unemployed, and only the breakthrough changed the situation completely. What if Witten had not read the thesis that I had sent to him? After all, Witten must have received tons of preprints and it was sheer luck that he happened to look whether this particular randomly picked up paper might contain something interesting. Of course, I had sent the work to many other well-known physicists but I still stubbornly insist that my work might have gone un-noticed. And what if Witten had not had time to read the paper carefully enough to realize the implications and intuitively realize how fascinating mathematics and physics it could lead to?
Some of us probably remember that around 1983 there was also a competing theory at market known as super-string model. Who knows, in absence of anything better it might have catched the attention of the physics community. And who knows, if my influential colleagues had managed to silence me, only few years of super string dominance might have been enough to establish it as a theory of everything for purely psychological and sociological reasons. The work in theoretical physics is incredibly demanding and requires fanatic devotion: you must be a total believer and you can work only with single theory during single life time. Believe me, theorists are not those cold rational thinkers that they might pretend themselves to be.
I hope that these arguments are enough to justify my light hearted attempt to imagine what might have happened during the next two decades if something had went wrong in the golden year 1983.
C. What could have happened
The following is one possible imagined history, and I admit that it ends as too many scifi stories tend to end: in the last chapter the author loses his control completely and even the last bits of plausibility are lost as the supposed to be climax is approached. Forgive me, I am not a professional science fictionist.
1. First super string revolution
The pressures were very strong for something new after the frustration created by un-successful quantum gravity theories relying on Kaluza-Klein philosophy. The first super string revolution occurred around 1984 since something had to happen. Witten came the intellectual leader of the field. What made this approach so fascinating was the promise for finiteness of the theory suggested already by the fact that point particles were replaced with 1-dimensional entities and the singularities of Feynman diagrams were expected to be smoothed out. Indeed, finiteness arguments left only 5 super string models into consideration.
There was also a severe problem: the connection with the experimental reality was lacking. Spontaneous compactification, the legacy from un-successful Kaluza-Klein approach to quantum gravitation, was the obvious proposal for how to get at least a semi-realistic theory. In absence of anything better it become rapidly something regarded as an established fact. Using conformal invariance as a guide line people ended up with Calabi-Yau manifolds as a reasonable guess for the 6-dimensional internal space (assuming 4 un-compactified dimensions): also this guess became soon regarded as an established fact.
A lot of work trying to deduce standard model was done but with a meager success. Spontaneous compactification destroyed also the original belief on the uniqueness of the theory. Ten years later the situation began to be desperate and the time was ripe for
2. Second super string revolution
The work after the first superstring revolution had taught that Kaluza-Klein program might not be enough to understand particle spectrum. This had led to the idea that perhaps also higher-dimensional surfaces should be accepted as derived dynamical entities. Also the TGD based idea that space-time might correspond to four-surface began to look attractive. In-officially people of course knew about TGD but it was too late to turn around and they took the risk and hoped that harmful TGD would emerge as a special case of some more bigger theory.
Some new language was necessary. The expression "Super string models" was replaced with "M-theory": in practice this meant more or less a polygon with five super-string models at is vertices and M-theory in its interior. Higher-dimensional surfaces were re-christened as branes. Since strings were the basic objects, branes were not regarded as primary dynamical entities but thought to result as some vague non-perturbative effect. The dream was that 4-branes would turn out to be unique and standard model gauge group would emerge. The dualities discovered long time ago provided a rather impressive technical tool and a voluminous industry of dualities emerged: probably no one knows which fraction of these dualities are true. The slogan was that if you cannot prove duality to be wrong in five minutes, it must be true.
No one can deny that M-theory, whose most fascinating property was advertised to be its non-existence, was a perfect media success. Spontaneous compactification had already introduced huge amount of confusion but after the introduction of branes the control was lost completely. A after a decade of swet, blood, and tears the situation had not improved in any essential manner. Worse, the situation began to look really desperate. There was still no idea about why the observed space-time dimension is four. The landscape of Calabi-Yaus had turned out to be immense. The standard model was still patiently waiting to be reproduced. To make situation even worse, web was suddenly full of blogs full of nasty commentary about the situation. The time was ripe for
3. Third super string revolution
Referring freely to the words of one of its fathers, the manifesto of the third super string revolution was that since M-theory cannot predict anything, and since M-theory is decided to be the theory, we must adopt a new definition of what science is. What is left to physicist is to try to discover whether the huge landscape of non-physical solutions might contain in some distant corner a solution resembling to some degree the universe we happen to live in, and use our own existence as a condition to deduce the predictions of the theory. No more even hope of predicting proton to Planck mass ratio. Not a very inspiring future vision for a young student of theoretical physics.
Yes...I am now in the last chapter of not so good scifi book and every bit of plausibility has obviously evaporated. True, the third super string revolution was unforgivably reckless imagination and I hope that my literary hallucinations did not irritate the reader too much. In our right mind we know that although theorists are true believers, they of also realize when it is not worth of continuing. Of course. Therefore "Postponed breakthrough of TGD" would have been the proper title of this section and probably already that of the earlier section. And now I also realize that I have been implicitly insulting my brilliant colleagues by suggesting that they might have spent ten years after first super-string revolution without realizing that super string model does not work! My sincere apologies. Take this as low quality science fiction, nothing more.
Matti Pitkanen