>Both carry current. But not power. Power is volts * amps, and the neutral is defined as zero volts (if you ignore the voltage drop).
What he has already pointed out is that voltage is a relative unit. Zero volts by itself is meaningless. It would be just as correct to say that the hot wire is at zero volts and the neutral wire and the rest of the planet are at 120VAC. Also earlier you mentioned that from phase to phase inside a house was 240v but phase to ground was 208v. This isn't correct and it's simple trigonometry to prove why. You can visualize voltage potential in any polyphase AC system as the distance between points on a circle. Ground is the center of the circle and the individual phase is a point on the circle offset by the phase angle. For a split phase system there is 180 degrees between the two phases and cos(0) - cos(180) gives you the fairly obvious distance of 2x the radius. This means for 120v from phase to ground you get 240v phase to phase. In a three phase system there's 120 degrees between phases so if you have 120v from phase to ground you have (cos(0)-cos(120))*120v=208v. For what you're saying to be possible you would need 98.85 degrees between phases which is obviously not a nice integer division of 360 degrees.
What he has already pointed out is that voltage is a relative unit. Zero volts by itself is meaningless. It would be just as correct to say that the hot wire is at zero volts and the neutral wire and the rest of the planet are at 120VAC. Also earlier you mentioned that from phase to phase inside a house was 240v but phase to ground was 208v. This isn't correct and it's simple trigonometry to prove why. You can visualize voltage potential in any polyphase AC system as the distance between points on a circle. Ground is the center of the circle and the individual phase is a point on the circle offset by the phase angle. For a split phase system there is 180 degrees between the two phases and cos(0) - cos(180) gives you the fairly obvious distance of 2x the radius. This means for 120v from phase to ground you get 240v phase to phase. In a three phase system there's 120 degrees between phases so if you have 120v from phase to ground you have (cos(0)-cos(120))*120v=208v. For what you're saying to be possible you would need 98.85 degrees between phases which is obviously not a nice integer division of 360 degrees.