Theory of everything: how progress in physics depends on asking the right questions

• Is it helpful in guiding scientists towards the discoveries that will advance our understanding to the next level?
• After all, good science relies on asking good questions.
• Arguably, the question “What is the theory of everything?” reminds us that good science doesn’t have to start with the best questions.
• We take turns, and the more we play, the quicker we seem to figure out which card has been chosen.
• The same is true of asking “What is the theory of everything?”: the goodness of a scientific question is not immutable.

Why a ‘theory of everything’?

• The model, which is written in a mathematical language called quantum field theory, describes how elementary particles move around and interact with one another.
• It explains why fundamental particles known as the W and Z bosons, which transmit the weak force, acquire a mass.
• The Higgs mechanism also explains why, at higher energies, these two forces start to behave as a single “electroweak” force.
• Now, if electromagnetism and the weak force combine in this way, why not all the forces in the Standard Model?
• The “theory” refers to the existence of some common mathematical framework that describes all of the “everything”.

Better questions

• They were motivated by better questions about what a theory of all the fundamental forces needs to explain and what it might look like, questions like: Why is there a huge discrepancy between the energy scales of the Standard Model and quantum gravity?
• Instead, these new questions have been reached by building on what has been learnt from developing and studying possible “Theories of Everything”, like string theory.
• And these new questions are good questions.
• The exciting thing is that they still may not be the best questions, and having them to guide us doesn’t necessarily mean that we know where we will end up.