Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is called the problem of … - Lee Smolin

The suggestion was that a positive energy proof for general relativity could be gotten by restricting supergravity to its bosonic sector, which is general relativity.

We show that some known classical results have particularly simple derivations within the Ashtekar formalism. These include Witten's positive energy theorem...

While most people... were seeking to modify the principles of either relativity or quantum theory, we surprised ourselves (and many other people) by succeeding in putting them together without modifying their principles.