Wednesday, January 02, 2008

Is it possible to change one's mind?

In Edge people tell how they changed their mind. Kea represented some remarks about these little stories which were indeed stimulating reading. What was meant to be a short comment in Kea's blog grew to a posting and I decided that my own blog is the proper place for it.

Garrett Lisi (some of us might still remember the Lisimania) questioned the belief that it is really possible to change one's mind. I could claim that I have changed dramatically my personal views about what we really understand about physics (reductionistic dogma, quantum effects important only in microscopic length scales, etc...). But when I think it again, I realize that this has been building a world view starting from child's innocence and relying on a new revolutionary idea which is my own rather than giving up a strongly held belief or getting inspired by an idea invented by some other.

It might well be impossible for me to admit that my beloved brain child TGD is a failure even if there were convincing arguments demonstrating it. What I have learned from the interaction with colleagues is that perhaps the best we can achieve is to articulate our personal beliefs about universe as precisely as possible and try to behave towards those who think differently. At best we could even pretend that we are listening on what other theoreticians try to tell;-). This is what I have become to believe but it might be time to give up this belief since Edge demonstrates that the feat of changing ones views is possible for some of us.

John Baez has lost his belief on quantum gravity. I cannot but share his skepticism if quantum gravity is defined by loading in the usual pile of prejudices about what quantum gravity must be (quantization of General Relativity, requirement that scattering amplitudes of GRT based theory are produced in lowest order by more general theories,...) and relying on incredibly naive generalization of the canonical quantization rules applied with reasonable success in finite-dimensional wave-mechanical systems. There is also second manner to guarantee the ultimate failure: isolate quantum gravity carefully from the rest of physics and do nothing but quantum gravity.

As a matter fact, I believe that even adding in high energy particle physics is not enough. Much more is needed: one must simply give up the cherished illusion that everything from nuclear physics to chemistry to astrophysics is nothing but standard model plus complexity. I believe that even consciousness must be brought in. It is a terrible loss that these stringy super brains supposed to build Theory of Everything close practically all incoming information channels feeding increasingly detailed information about Everything.

Steinhardt, one of the architects of inflationary scenario, had lost his belief on inflation and his article taught to a non-specialist ugly things not mentioned in the popular articles written in the usual over-optimistic salesman tone. The core of Steinhardt's argument is that the classical picture about inflation making the desired predictions must be replaced with quantum view. This however destroys all nice predictions: fluctuations are not smoothed out but amplified and even physical laws change in observable scales.

My own TGD based view has been that inflation is wrong. It is possible to imbed De Sitter space-time in 8-D imbedding space H=M4×CP2 of TGD as Roberton-Walker cosmology but the 4-D space-time sheet representing it fills densely D>4-dimensional surface in H and even a slightest deformation implies infinite number of self intersections. It might be a matter of taste whether to see this as a catastrophe or not, and one might play with the idea that here are the TGD variants of branes. My own model is based on quantum criticality for a phase transition increasing gravitational Planck constant implying the desired fractal long range fluctuations and flat 3-space (no dimensional parameter in 3-geometry). The predicted cosmology is unique apart from a parameter telling its duration so that the model is testable. It also predicts accelerated expansion.

I hope that Sabbagh's (author of Riemann Hypothesis) loss of belief on experts could become a disease infecting entire scientific community. Personally I am grateful for my colleagues that they so generously helped me to get rid of the belief on expert wisdom in theoretical physics. We want to believe that things are better beyond the sea and also I did my best to believe that in mathematics the situation might be different but some experiences relating to Riemann hypothesis killed also this illusion.


At 12:22 PM, Blogger Kea said...

I wish I could say Cheer Up, Matti, but things do look dim. The great irony in John Baez's position is that he's currently working on QG without fully realising it (this Geometric Representation Theory is important) whereas before, whilst playing with the loopies, he never really was.

At 9:46 PM, Blogger Matti Pitkanen said...

What makes me happy is that people like John Baez are finally realizing that the best manner to fail is to restrict attention only to quantum gravity or to TOE understood as "the physics in Planck scale". This restriction of attention to essentials might be the best strategy for getting phone call in Stockholm but it is not the manner to solve deep problems.

The geometric representation theory, TQFT, braids, etc.. provide tools for any reasonable theory of everything but trying to force these tools to produce GRT results in lowest order for scattering amplitudes is not wise. Also assuming that these tools as such are enough would be like trying to deduce existing physics from calculus. I suggests that we should forget methods for a moment and return to the fundamental questions about quantum physics.

About cheering up: there are things which make me unhappy. Am I really doomed to repeat the rest of my life the question "Who is mad: is it me or the entire community of theoretical physicists?";-)? I am already now quite convinced about the correct answer.


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