Today’s Google Doodle celebrates British logician and philosopher John Venn, who would have been 180 today. The clever interactive cartoon turns the two Os in Google into a Venn Diagram, which Venn invented around 1880 and which is now indispensable to set theorists, data visualizers, statisticians, and computer scientists. It has also spawned many an Internet meme.
Born in Yorkshire in 1834, Venn got his degree in math at Caius College Cambridge, where he returned to lecture in moral science after being ordained an Anglican priest. (He later resigned from the clergy, finding religion incompatible with his philosophical beliefs.) He called his diagrams "Eulerian Circles," and they evolved into a system for visualizing relationships between finite groups of sets that was both poetic and practical. In designing more complicated diagrams for higher numbers of sets, he was intent on finding "symmetrical figures . . . elegant in themselves," as he described in Symbolic Logic.
The Doodle designer Mark Dutton worked with Google Doodle engineers Corrie Scalisi and Mark Ivey to create a whimsical animation that lets users make their own colorful Venn diagrams, revealing relationships between random sets. Click on descriptors like "tiny," "has wings," and "thrives in cold" and see where they overlap with others, like "musical," "sea life," or "mammals." ("Tiny" and "mammals" overlap and yield an animation of a little mouse, for example.) "Things Venn imagined in his lifetime" probably overlaps very little with "what the Internet has done with Venn diagrams."