String theory pros and cons

In this video I explain why so many physicists believe in string theory but that it also comes with a number of problems. It requires the existence of additional dimensions of space (which we do not see), of new particles (which we do not see), and of new fields (leading to deviations from Einstein’s general relativity). It has trouble coping with the cosmological constant and the dream that string theory would be a unique theory of everything has failed due to the discovery of the string theory landscape.