(October 30, 2016 at 4:43 pm)Alasdair Ham Wrote:(October 27, 2016 at 7:59 pm)Jehanne Wrote: Think about it in terms of voltages on a wire, positive to negative, and back; what is "zero voltage"? It is the ground, the voltage that the Earth is at.
Well, I wasn't being metaphrorical.
Colors exist in the sense of qualia. Zero only exists as a concept.
If I have a galvanometer, I can measure zero electric current:
http://hyperphysics.phy-astr.gsu.edu/hba...an.html#c1