The title of the article tells the message. The article repeats the same old wisdom: string model is the only viable model to describe physics. The problem is of course that string model fails to predict anything - as the title indeed tells. The natural reaction would be a simple question: "What went wrong?" but this question is not made. Instead one just gives up the very idea behind physics - that of finding principles that predict the universe as we observe it. Of course, it will predict also many other things but this universe inhabited by us must come out naturally.
In order to understand this it is good to notice that there are two views about mathematics and also physics.
- In the first view one tries to identify fundamental structures: classical number fields represent excellent example in this aspect. There are only 4 continuous number fields with real topology: reals, complex numbers, quaternions, and octonions. There is infinite number of p-adic number fields plus finite fields.
- In second view one tries to be as generic as possible and allows all imaginable structures.
I must admit being old-fashioned. By taking a sharper look, one begins to realize that this turning of coat is basically about the infinite vanity of human egos. Around 1984 when superstring mania began there was a horrible hurry to write epoch changing papers in the hope of even receiving a Nobel. No-one had time to think whether the basic idea that 2-D string world sheets are fundamental, is realistic. This idea would be realistic, if we lived in 2-D space-time. We however live in 4-D space-time and it would be natural to take 3-D surfaces to be the basic objects: they would represent either particle and 3-space depending on the the size scale of observer.
The idea was that spontaneous compactification would give 4-D space-time effectively. Soon it began to become clear that string model does not work as expected but it was quite too embarrassing to admit this: when too many people are wrong they decide collectively that they are right. Branes were introduced in the hope that 4-D space-time could correspond to brane. Around 1993 or so M-theory emerged as the last desperate attempt to make something out of superstring models. The outcome was landscape and almost a complete loss of predictivity. There were however some general predictions: SUSY at LHC energies, which was not found and the wrong sign of cosmological constant. This led eventually complete re-evaluation of what the great dream should have been: it was the landscape rather than unification of fundamental interactions and quantum theory of gravity!
I was lucky and managed to avoid of dropping to this collective trap. I had started towards the end of 1977 with the basic idea of TGD about space-time as 4-D surface in higher-dimensional space-time of form H=M4×S. This to solve the energy problem of general relativity due to the loss of Poincare symmetries: now they were lifted to H. It soon turned out that TGD can be also seen as a generalization of hadronic string model obtained by replacing string with 3-surface. I published my thesis 1982, 2 years before the first superstring revolution.
In the middle of superstring hysteria the obvious idea about the replacement of strings with 3-surfaces was missed despite that even the fundamental conformal invariance of 2-D string world sheets generalizes for 3-D light-like surfaces by their metric 2-dimensionality. Particles would have as basic building bricks 3-D light-like 3-surfaces at which the signature of the induced metric changes from Minkowskian to Euclidian. This makes 4-D space-time and the decomposition of higher-D imbedding space as H=M4×S unique.
S must be chosen so that H is completely unique both physically and mathematically. S= CP2 provides a geometrization of standard model symmetries, quantum numbers, and classical gauge fields plus gravitation. S= CP2 is also unique also mathematically: only CP2 and S4, E4 (and M4 in generalized sense) allow twistor spaces with Kähler structure. For this choice of H one has also so called M8-H duality . M8 provides number theoretical description using classical number fields part as a dual for the geometric description in terms of H (one could speak of number theoretical compactification which is not dynamical compactification which was hoped to give 4-D space-time in superstring models).
I am proud to confess that TGD view represents the old-fashioned view about unification: extreme local simplicity of dynamics at the fundamental level but topological complexity in all scales for many-sheeted space-time. At QFT limit (standard model plus GRT) the many-sheeted space-time is replaced with single sheeted one in long length scales. Topological information is lost and local dynamics becomes complex. TGD also changes the world view: length scale reductionism is replaced with fractal hierarchies, p-adic physics for various p-adic number fields and real numbers fused to adelic physics brings cognition to the realm of physics, quantum theory of consciousness baed on zero energy ontology and quantum biology emerge as applications or rather essential parts of fundamental physics.
For a summary of earlier postings see Latest progress in TGD.