Jim Peebles (Princeton) visited today. Roweis and I spent an hour or so advertising to him our data analysis projects. Late in the day he gave a talk on the history of cosmology, which made a number of remarkable points, like that Hoyle was (almost) the first person to identify the cosmic microwave background (despite the fact that he thought it was impossible). An argument broke out about the importance of Friedman; Peebles takes the (tough) view that to be really important in cosmology you must have not just done theory but connected it directly to experiment, or not just done experiment but had the theorists realize that it was relevant. That's a high bar.