This Saturday in Johnstown, Pennsylvania, Center for Science & Culture Fellow Paul Nelson will debate Texas Tech philosopher of biology Joel Velasco on the question of universal common ancestry — sometimes referred to as Darwin’s Tree of Life (TOL). If you don’t happen to be in the area, you can also watch online. That’s March 29, at 3 pm in the auditorium of Penn Highlands Community College.

For online viewers, the Johnstown Daily American will be providing the live stream for the event, titled “The Origin of the Species: A Debate over Common Descent and Separate Ancestry.”

Unfortunately, the event was originally — and inaccurately — billed by organizers as a “Creation vs. Evolution” debate, and the newspaper is still listing it with that description. In reality, the debate is not about “creation,” let alone “creationism.” Indeed, it won’t even be a discussion of intelligent design, because common descent is perfectly compatible with the finding of evidence of purposeful design in nature. Instead, the event is supposed to be a discussion about the current scientific evidence relating to one particular facet of modern Darwinian theory. It’s tiresome to have the “Creation vs. Evolution” label stuck unthinkingly on nearly every critical discussion relating to modern evolutionary theory, but it’s symptomatic of our times. Many people today would rather use a label to dismiss a position than take the effort to carefully explore the actual evidence.

Well, here’s your chance to explore some evidence. According to the TOL historical geometry, all organisms on Earth share genealogical relatedness, descending by modification from the Last Universal Common Ancestor (LUCA). Velasco will be defending the reality of the TOL, and the existence of LUCA (although not perhaps as an identifiable organism), whereas Nelson will challenge both, and argue that living things fall into discrete, independent groups, representing separate trees within a Forest of Life.

Several aspects of this debate make it unique. Both Velasco and Nelson wrote their PhD dissertations on the topic of the TOL and common ancestry: Velasco at the University of Wisconsin-Madison, and Nelson at the University of Chicago. Velasco was mentored at UW-Madison by leading philosopher of biology Elliott Sober, who has cited Nelson’s work in his scholarly publications (see here for instance). Both Nelson and Velasco will argue that intelligent design does NOT require endorsing separate ancestry — the Forest of Life. In fact, some ID advocates stand on Velasco’s side of the aisle on this. With the usual debate categories thus scrambled, the interchange promises to be very interesting.

Image: Darwin’s “Tree of Life,” from On the Origin of Species, 1859/Wikpedia.