My students know I never tire of emphasizing the self-corrective nature of science: how scientific theories are always dynamic theories, constantly being tested against reality, discarded if they fail the test, and continuously revised and refined as we get a better and better approximation of truth. A good example of a scientist who put his own ideas, his life's work, through this process of continual testing and refinement is of course, Charles Darwin. We all know about how he hesitated to publish his theory of evolution by natural selection for c.20 years, 15 of those after he had written out a detailed "outline", but his work didn't stop with the publication of On the Origin of Species in 1859 (we're coming up on the 150th anniversary of its publication in November this year). He continued to tinker with the book, tweaking the language, refining his arguments, and responding to criticisms as well by eventually adding a whole chapter on the subject - and publishing a total of 6 editions of the book over the next 13 years. Students taking Evolution at Fresno State have in recent years been reading the 1st edition of the classic book, chosen because we want them to experience the book as the world first encountered it, before Darwin had to worry about responding to critics. But the 6 editions themselves represent an evolution of sorts, with favored passages being preserved and refined while others were selected out. Darwin scholars have been studying the differences, and now the rest of us also have a new way to appreciate this textual evolution, through a fascinating new visualization created by Ben Fry of Seed Visualization's Phyllotaxis lab. This dynamic Flash graphic takes you through all the changes to the text much the same way a phylogeneticist might compare DNA sequence changes across a taxon's evolutionary lineage. And as you can see in the gel-like excerpt I've put at the top of this post, you can click on any "band" in any portion of the text-gel to read the mutations therein! Go check it out - its really cool! And read also Ben Fry's interview in Seed about this visualization.