I'm sure this was asked before on here. The title is pretty self explanatory. Personally I don't know a good answer to this question. On the one hand you'll have a group of people who are very smart and are exploring why nature is the way it is. Also if there are more theoretical physicist it might have a positive affect on math and science education because more people that know there stuff would be available to teach it. On the other hand though it would mean more people out there who know how to make dangerous weapons.