It was a relatively low-research day, although I did check in with So Hattori and Dun Wang on their projects. I had a short conversation with Hennawi about next projects with SDSS-III and SDSS-IV spectroscopy. (Today is the last day of SDSS-III observing; SDSS-IV starts tomorrow!) We talked about Hennawi's Princeton-esque philosophy that great science happens when there are precise measurements that can be made and precise theoretical predictions for those measurements. This is a high bar for astrophysics: Many research areas either have no precise measurements, or no precise predictions, or neither. Interesting to think about projects through this lens. I am not particularly endorsing it, of course, since lots of science happens through discovery and description too.