Thanks for the response, Bill.

Let's stick with the potential energy for a moment.


If, instead of picking up the stone, I dig a deep hole beside it, then push it in, can I be said to increase its potential energy when I dig the hole, or when I push it over the edge? On the other hand, perhaps it would be more accurate to say that the stone already had the potential energy to take it to the centre of the Earth, but there was rather a lot of matter in its way. This is really the point I was working towards; that every particle of matter in the Universe has enough potential energy to bring it back into contact with every other particle. All we do when we pick up rocks, or send craft into space, is make a slight local alteration to potential energy that is already there.

There never was nothing.