Quote from Calíbre
So then:
50% empty = half empty = 0
50% empty = half 0ml = 0
50% empty = 50% of 0ml = 0
still stands.
50% empty = half empty = 0
50% empty = half 0ml = 0
50% empty = 50% of 0ml = 0
still stands.
If the glas is 50% empty then the rest must be 50% not empty. So 50% empty can never be 0 because one would neglect the rest that makes up the 100%.
To make this clear, imagine a graph where the vertical axis is fullness and the horizontal axis is emptiness. A line is drawn from 100% fullness to 100% emptiness and exactly in the middle of that line we've got a point that is 50% empty as well as it is 50% full.
Also you could express the emptiness not in the amount of water but in the amount of free space in the glass. If the glas is empty the free space is maximal and 50% of that certainly won't be zero.
________________