But their unity is determined by the outpouring for which the jug is fitted as a jug. The twofold holding of the void rests on the outpouring. In the outpouring, the holding is authentically how it is. To pour from the jug is to give. The holding of the vessel occurs in the giving of the outpouring.
Holding needs the void as that which holds.
The nature of the holding void is gathered in the giving. But giving is richer than a mere pouring out. The jug's jug-character consists in the poured gift of the pouring out. Even the empty jug retains its nature by virtue of the poured gift, even though the empty jug does not admit of a giving out. Martin Heidegger, The Thing .