Particularly theoretical physics. For example, what % can understand string theory? Do most have a pretty good hold on cosmology, high energy physics, etc.. no matter what their speciality? Is there anyone qualified to post in every section of this forum? It seems like people like Weinberg and Hawking have a wide range of contributions across many areas of the field. Is this common? How do the degrees work? Like do you get a degree in physics with a speciality in say..relativity? Thanks for the info.