Friday, January 27, 2017

There's a Paradox

What about Paradoxes?  Paradoxes have been a central part of philosophical thinking for centuries.  For example, Achilles and the Tortoise comes from the 5th century BC.  I went to and browsed through the best-known paradoxes.  I chose the discussion on the Raven Paradox for today.  At  they're presented with cartoons, so are quite fun.


Also known as Hempel’s Paradox, for the German logician who proposed it in the mid-1940s, the Raven Paradox begins with the apparently straightforward and entirely true statement that “all ravens are black.” This is matched by a “logically contrapositive” (i.e. negative and contradictory) statement that “everything that is not black is not a raven”—which, despite seeming like a fairly unnecessary point to make, is also true given that we know “all ravens are black.” Hempel argues that whenever we see a black raven, this provides evidence to support the first statement. But by extension, whenever we see anything that is not black, like an apple, this too must be taken as evidence supporting the second statement—after all, an apple is not black, and nor is it a raven.
The paradox here is that Hempel has apparently proved that seeing an apple provides us with evidence, no matter how unrelated it may seem, that ravens are black. It’s the equivalent of saying that you live in New York is evidence that you don’t live in L.A., or that saying you are 30 years old is evidence that you are not 29. Just how much information can one statement actually imply anyway?
Here is Wikipedia's summary of the Raven paradox: 
Raven paradox: (or Hempel's Ravens): Observing a green apple increases the likelihood of all ravens being black.

I was in Toronto yesterday, and found this reflective material on the side of the umbra store near Queen Street West.  I had thought I might find some pink water reflections, but this material created prism/rainbow reflections. The first picture shows the photo without adjustments, and the next few show the finished result, with the pavement turned to black. 

No comments:

Post a Comment