In the 17th century, the British #philosopher John #Locke gave us one of the most relatable thought experiments in history. In fact, it was probably one of the earliest #philosophical questions I had.Imagine that there are two perfectly healthy people with perfectly functioning sense organs on a walk, and one turns to the other and says, “What a beautiful blue sky!” And the other one nods along. But the question that John Locke raises is how do we know that the blue that one person sees does not