By Don Howard

Every spring for the last 12 years, the Seven Pines Symposium has gathered a group of historians, philosophers, and scientists together in a northwoods lodge for the purpose of exploring important foundational questions in physics and allied areas. The twelfth Seven Pines Symposium occurred 7–11 May 2008, focusing on “The Unknown Universe: Dark Energy and Dark Matter.” Its setting was once again The Outing Lodge at Pine Point, a few miles outside of Stillwater, MN. As before, all participants enjoyed the hospitality of our hosts, Lee Gohlike, founder and sponsor of the Symposia, and his wife Carlota Estevez. Superb cuisine, a cozy lodge ideally suited to such gatherings, a beautiful rural setting with hiking trails and nearby lakes, and the annual spring migration to delight bird-watchers—what more can one want in a meeting venue?

Seven Pines Symposia are designed to maximize time available for free-ranging discussion, the brief, more-or-less pedagogical talks mainly serving to seed the ensuing conversations. This year’s program began on the morning of Thursday, May 8, with an introduction to the goals of the Symposia by Gohlike, followed by a session about the “History of the Cosmological Constant” featuring talks by Michel Janssen (Minnesota) on “Why Einstein Introduced the Cosmological Constant,” and by John Earman (Pittsburgh) on “ The Cosmological Constant, 1917–1997.” In the afternoon session, we shifted the focus to “Evidence for Dark Matter.” William Vanderburgh (Wichita State), gave us “A Historian’s Perspective,” and Jim Peebles (Princeton) offered “A Scientist’s Perspective” on the subject. On Friday, we began the day with “Evidence for Dark Energy.” Michael Turner (Chicago) presented both “An Observational Perspective” and “A Theoretical Perspective.” After lunch we moved on to “The Cosmological Constant Problem.” Jeff Harvey (Chicago) talked first about “The Nature of the Cosmological Constant Problem,” and then Shamit Kachru (Stanford) addressed the question, “Does the String Theory Landscape Provide an Explanation for the Cosmological Constant?” Saturday’s program began with a session on “Dark Matter: Experiment and Theory,” which featured Bernard Sadoulet (University of California, Berkeley) speaking about recent experimental work, and Serge Rudaz (Minnesota) giving us an “Overview of Dark Matter Candidates.” The regular program concluded on Saturday afternoon, as we discussed “The Way Ahead. . . .” Mark Trodden (Syracuse) spoke on “Alternatives to Dark Matter and Dark Energy,” and Jim Peebles (Princeton) talked about the general session theme. Sunday morning was devoted to a long wrap-up discussion ended only by the participants’ scheduled departures for the airport.

Symposium founder Gohlike has long been interested in the history and philosophy of science, having pursued those interests through graduate studies at the Universities of Minnesota and Chicago. For help in planning, he established an advisory board now consisting of Michel Janssen (Minnesota), Chair, John Earman (Pittsburgh), Geoffrey Hellman (Minnesota), Don Howard (Notre Dame), Serge Rudaz (Minnesota), and Robert M. Wald (Chicago). Also participating in Symposium this year were Ernan McMullin (Notre Dame), Antigone Nounou (Minnesota), Chris Smeenk (Western Ontario), Roger Stuewer (Minnesota), William G. Unruh (British Columbia), and several physics graduate students and post-docs from Minnesota. The thirteenth annual Seven Pines Symposium is tentatively scheduled to be held 6–10 May 2009, with a focus on foundational topics in condensed matter physics.