the slippery "F" word - my solution

[theVOID]

Here's my example. Say there is an island with no contact of the outside world. The island teaches every child from birth onward that the sky is purple. Now, the sky happens to be really blue.

False analogy, in this case they are simply using a different label to describe the same thing, neither of them is wrong because the world 'blue' does not have any more inherent value in describing the colour of the sky than the word 'purple' does, it's only a label than points to a concept.

As long as the concept is agreed upon, ie the wavelength of light captured by the eyes interpreted by the brain, what they name the concept is only a linguistic obstacle for communication and not an instance of them being right or wrong.