I'm looking for Paul Burka. Professor Paul Burka.He's teaching a class on Tocqueville that must have begun about twenty minutes ago,and I can't seem to find his classroom. The man I'm talking to is a giant with a gray mustache,clad in jeans, T-shirt moist with perspiration,taking the fresh air with a dozen or so youngsters sitting,like him,on wicker chairs in a sunny,comfortable lobby in the immense University of Texas at Austin.