There’s a new philosophy of science book out, Richard Dawid’s String Theory and the Scientific MethodThe book seems to be an elaboration of these papers, downloadable for free: Underdetermination and Theory Succession from the Perspective of String Theory, On the conflicting assessments of the current status of string theory, and Realism in the age of string theory.
The argument is that a lot of big-shots work on string theory, so it must be science. The theory is unique because it claims to explain everything, while actually explaining nothing. Since the theory cannot be tested, we have to accept new definitions of science and realism. Some really smart people have opinions about what is aesthetically pleasing, and that can substitute for experiment.
Yes, that's it. He is trying to promote string theory, but his empty argument show that the theory is a failure by any objective standard.
The three reasons behind the near-certainty about the theory's validity are:So if these super-smart guy had a mystical belief in unicorns or astrology, and string theory were perceived as better than the alternatives for the purpose, then they study string theory. The problem with this argument is that there is no good reason to believe in unified field theory, and no good reason for believing that string theory would be progress towards that end.
the non-existence of alternatives ...
Concerning the first argument, it is the actual explanation why the top bright theoretical physicists focus this high percentage of their intellectual skills on string theory. They simply divide their mental powers to all promising ideas, with the weight given by the degree to which they are promising. Because one may approximately say that there aren't any other promising "big ideas" outside string theory, people can't work on them.
"there is no good reason to believe in unified field theory, and no good reason for believing that string theory would be progress towards that end."ReplyDelete
Maybe you should try to learn about this stuff before blasting your ignorance all over the internet. This sentence indicates that you're about a hundred years behind the cutting edge in your understanding of physics research. Unified field theories were studied by Einstein and Kaluza-Klein, but pretty much nobody nowadays thinks that the fundamental forces should be unified by a field theory. In particular, string theory is NOT a quantum field theory.
The above book says: "String theory was first proposed as a universal theory of microphysics in 1974 ... It is a quantum theory that aims at reproducing the interaction and symmetry structure of a gauge field theory." [p.10]ReplyDelete
I don't know what hair-splitting point you are trying to make. It is true that string theory fails to explain any particles or fields found in nature. But the purpose of the theory is to explain them all. It certain is, or at least tries to be, a unified field theory.
Just ask yourself, does string theory aim to explain electromagnetic fields, weak fields, string fields, and gravity fields? If so, then it aims to be a unified field theory.
"I don't know what hair-splitting point you are trying to make."ReplyDelete
The point is that you don't know what the term "unified field theory" means. When you say that something is a "field theory" you mean that the theory is formulated in terms of a spacetime manifold with a collection of classical field configurations. We've known for a long time that gravity cannot be quantized as a field theory. String theory is therefore not formulated as a quantum field theory. Rather, it is a quantum mechanical theory that gives an effective description of gravity in its low energy limit.
I am using the term Unified field theory as it is defined on Wikipedia. That article mentions string theory as a promising way to unify the known fields.ReplyDelete
We have known for a long time that string theory fails to unify any fields, and unification is the stated purpose of the string theorists.
Uh, no. That article says "The 'theory of everything' and Grand Unified Theory are closely related to unified field theory, but differ by not requiring the basis of nature to be fields".ReplyDelete
So are you trying to say that string theory is not a unified field theory, but a 'theory of everything' or a Grand Unified Theory instead?ReplyDelete
Regardless of which term you prefer, string theory is a theory that aims to unify the fields. Not successfully, but that is what its leaders claim that they are trying to do.
"So are you trying to say that string theory is not a unified field theory, but a 'theory of everything' or a Grand Unified Theory instead?"ReplyDelete
"Until this [non-perturbative] region can be probed, we don’t know if string theory is a theory of everything — or a theory of nothing!" -- M. Kaku, 'M-Theory: The Mother of all SuperStrings'