It didn’t take Carolyn E. Shapiro long to spot the differences between teaching law and being the state’s solicitor general. “When you’re a professor, there’s a certain amount of — at least, theoretically — thinking deep thoughts,” she said. “And being SG is a little bit more like drinking from a fire hose. The stuff is coming at you so fast, it’s hard to stay upright.” Speaking to about 40 attorneys and judges at a lunch event Wednesday at the Union …