Presenting the Wesley C. Salmon Memorial Lecture, November 17, 2025, at 3:00 pm
The Department of History and Philosophy of Science, The Department of Philosophy, and The Center for Philosophy of Science, University of Pittsburgh Present:
“An Altitude or Attitude Adjustment? Gravity’s Challenge to Thermodynamics”
Craig Callender, UC San Diego
William Pitt Union Building– WPU Assembly Room
Monday, November 17, 2025, 3:00 PM
Abstract: Consider a simple column of gas. Make the column big enough so that gravity matters. Does a temperature gradient arise (in equilibrium)? Surprisingly, this question was the subject of debate by Maxwell, Guthrie, Burbury, Boltzmann, and Loschmidt, illustrating that simple systems can raise deep foundational puzzles. The debate was resolved in favor of no temperature gradients arising. In an exciting but under-explored twist to this history, general relativity predicts that a temperature gradient does in fact arise. How do we reconcile this effect (the Ehrenfest-Tolman) with the historical resolution? Do we need an altitude adjustment to temperature, as is commonly thought, or do we instead require an attitude adjustment to our understanding of thermodynamics?
Wesley C. Salmon joined the Department of Philosophy as Professor and Chair in 1981. He held the rank of University Professor from 1983 until his retirement in 1999. He exerted a profound influence over philosophy of science as it was practiced in Pittsburgh and internationally. His investigations into scientific explanation, causality, probability and induction and the philosophy of space and time provide a model of insight and clarity, in both thought and word. He set an example personally through his unfailing integrity and kindness. He died in 2001. His memory survives through the scholars who study his work and the many who remember him personally, with respect and admiration.
The Wesley C. Salmon Memorial Lecture Fund has been established to support an annual lecture by a prominent scholar in philosophy of science in honor of Wesley Salmon.