Emeralds Are Grue, Sky Is Bleen

Jan. 2, 210
PASADENA–Responding to recent panic surrounding the sky’s dramatic change in color, a team of logicians and philosophers of language at the California Institute of Technology has released findings designed to calm the public and explain the transformation. “We have heard the press speculation that the change in the color of the sky is related to an unexplained and possibly toxic pollution event,” notes Caltech Professor of Nomenclature Dorinda Pocopollo. “Our aim with this press conference is to dispel those rumors. This is not an ecological catastrophe, as many have feared, but a logical one.”

Scientists and religious leaders alike have struggled to account for the January first transformation of the traditionally blue sky to a shade of green likened by many to key lime pie. In an effort to diffuse apocalyptic and alarmist fervor, a number of scientific institutions have offered preliminary analyses and have taken efforts to disseminate available concrete facts about the transformation.

The U.S.-based National Center for Atmospheric Research (“NCAR”) announced late yesterday that the change was not coordinated with any “apparent modification of atmospheric state or behavior” while atmospheric observatories and weather stations worldwide report no measurable change in the physical properties of observable light reflected from the sun through the earth’s atmosphere. “As far as we can tell the sky is still blue,” exclaims NCAR Executive Director Herman Grout. “Even if I didn’t trust my own eyes, though, I’d have to trust the 30 billion other eyes out there that also are telling me it’s green. At this point it seems safe to say the sky is, indeed, green. There are, however, no indications that it is falling.”

Noting that the largely overshadowed change in the color of emeralds occurred at the same time as that of the daytime sky, Professor Pocopollo’s Caltech team speculates that the changes are related to a traditional logic problem known as Goodman’s paradox. “Goodman’s paradox is a challenge to our intuitive understanding of induction,” explains Professor Pocopollo. “It postulates a language in which the properties ‘blue’ and ‘green’ are replaced with ‘grue’ and ‘bleen.’ Something is ‘grue’ if it is ‘green’ before a certain time and ‘blue’ after it, while something is ‘bleen’ if it is ‘blue’ before and ‘green’ after.”

Discussions of the paradox have traditionally used emeralds as a heuristic example, and typical analyses have hypothesized a definition of ‘grue’ objects as objects that are green before 2100 and blue afterward. “We aren’t offering a conclusion concerning what’s happened,” opines Professor Pocopollo, “But we would like to point out that the change in the color of the sky, and in that of emeralds, has been fairly accurately placed at 12:00:01am Greenwich Mean Time, and while Goodman’s paradox does not traditionally use the sky as an example of a potentially ‘bleen’ object, the sky is the paradigmatically blue object.”

Asked to speculate about the implications of her team’s findings, Professor Pocopollo indicated that, rather than a sign of an impending apocalypse or ecological disaster, the green sky may simply be “the first fact about the state of the world to confirm that our language is out of step with the case. Until now we’ve concluded, inductively, that the sky is blue; now we’ve learned that it is most likely bleen. That’s an inductive mistake that certainly isn’t going to kill us, however much it may shake the entrenched foundations of our confidence in the familiar inductions on which we rely in everyday life.

“If you ask me, and if the green sky is related to Goodman’s paradox, people shouldn’t worry about anything else than getting used to saying ‘bleen’ and ‘grue,'” confided Pocopollo. “The thing I worry about is what this might portend for Hume’s paradox. Hume pointed out that our belief that the sun will rise tomorrow is inductively derived from our habitual experience of the daily rising of the sun. If we’re as wrong about that as we were about the color of the sky we could be in for a rude surprise tomorrow morning.”