I am a Mathematics and Physics double major, currently in my second year. I really enjoy both subjects, but my interests are progressing towards Theoretical physics/mathematical physics. My academic goal is to improve my understanding of how the universe works and thus I would like to persue a Phd in the area of High energy Physics or the mathematical basis of these theories. Despite this, I do enjoy the rigour and proofs of pure mathematics and would like to persue a masters in a geometric area (such as differential geometry or Topology) before starting my Phd. Is this unrealistic? I am aware that this will take time, but i feel that it will be beneficial. My main motivation for doing this is to gain an understanding of the mathematical proofs and framework, rather than just taking a mathematician's word for it and using them as tools in physics. I would also like to gain the experience of working in a field of pure mathematics just for self fulfillment. For instance John Baez is a mathematical physicist, but has quite a broad understanding of mathematics, and i wish to emulate this. I have been told that mathematical physicists are better off being trained in mathematics departments, and this leaves me at a loss. I understand that no one can attain an understanding of all the areas of mathematics and physics, let alone research expertise, but i would enjoy being a theoretical Physicist with a deep understanding of the mathematical objects i am working with, maybe even using the intuition i develop to guide pure mathematicians (as Witten does).