Most of Physics in the twentieth century has been obsessed with the quest to find the “Theory of Everything” – a model for reality that would explain all the observed phenomenon of the Universe in one elegant expression based on fundamental quantities.
The whole enterprise got underway after Maxwell’s unification of Electricity and Magnetism and the resulting understanding of the wave nature of light, the prediction of the speed of light and the impetus for Special Relativity. Feynman (et al) came up with the Electo-Weak theory which folded in the weak nuclear force into Maxwell’s model and earned Sin-Itiro Tomonaga, Julian Schwinger and Richard P. Feynman the Nobel Prize for Physics in 1965. Nowadays most people recognize the power of the SU(4) based Standard Model as managing to include the Strong nuclear force into the Electro-Weak model.
The issue has been whether or not Gravity (and any additionally discovered forces) could ever be added successfully to the existing Unified models.
According to Stephen Hawking, in an essay in Scientific American, there may be no hope for the quest…
“[Hawking is quoted…]
‘In our view, there is no picture or theory-independent concept of reality. Instead we adopt a view that we call model – dependent realism: the idea that a physical theory or world is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. According to model – dependent realism, it is pointless to ask whether a model is real, only whether it agrees with observation. If two models agree with observation, neither model can be considered more real than the other. A person can use whichever model is more convenient in the situation under consideration.’
[Physics Buzz continues] This view is a staunch reversal for Hawking, who 30 years ago argued that not only would physicists find a theory of everything, but that it would happen by the year 2000. In his first speech as Lucasian Chair at Cambridge titled ‘Is the end in sight for theoretical physics?,’ Hawking argued that the unification of quantum mechanics and general relativity into one theory was inevitable and that the coming age of computers would render physicists obsolete, if not physics itself.
Of course, Hawking has become rather well known for jumping way out on a limb with his public remarks and for decades he embraced supergravity as having the potential to solve theoretical physicist’s ills, even hosting a major conference on it in 1982. However, but Hawking has never harbored allegiances to theories that describe a physical reality.
So, while two well-known physicists coming out against a theory of everything is compelling, it really shouldn’t seem like anything new for Hawking.
‘I take the positivist view point that a physical theory is just a mathematical model and that it is meaningless to ask whether it corresponds to reality. All that one can ask is that its predictions should be in agreement with observation.’
Read the full article here.
Nice shout out to the positivists there. ‘Course as a post-positivist, I’d say that there was more to the fundamental nature of the models than Hawking would, but then he’s a much better physicist than I, so take my quibble with a box of salt.