Since Nelson Goodman’s publication of Fact, Fiction, & Forecast,1 philosophers have discussed the color known as grue, which seems identical to green before time T, but which seems identical to blue after time T. The problem with identifying grue things, of course, is that no one knew when time T would occur.
Well, thanks to The Flying News and the research of Tot Tibor, we now know when time T will occur. So how will this help us to identify the color grue? Since most modern cameras are grue compatible, comparing a photograph of an object with the original object won’t be any help: grue compatible cameras take grue photographs of grue objects. After much thought and experiment, we have an exclusive and patented method of determining whether an object is or is not grue. You will need a suspected grue object (the test object), a certified green object, a certified blue object, and a watch or other timepiece capable of displaying both time and date. Take the suspected grue object and place it on a comfortable surface. Write down whether the suspected grue object is similar in color to the green or to the blue object. Set your clock or timepiece to any time before time T, and show the time and date to the grue object. After you are sure that the test object has seen the time and date, compare the test object’s color to your certified green and blue objects. If the test object is not similar to the object to which it was similar before, then you have discovered a grue object. Note that it is important to have certified green and blue objects for comparison. If you don’t, then you might end up with grue and bleen objects, and your test would be invalidated.
- Cambridge, MA: Harvard University Press, 1955. ↩