Until one player has doubled, the cube is in the middle. But once Black has doubled you, he has given you an important weapon which he himself does not have, i.e. control of the cube, and if the game gets to a position which would otherwise be equal, you have a distinct edge. First, you may get such an advantage that when you double he has to drop. Yet one piece of luck could have won the game for him. So, by having the cube, you have won a game you might have lost. Secondly, in the situations where you redouble him and he takes (whether rightly or wrongly), you are obviously going to win twice as much, on average, as if he had not earlier doubled the stake himself.
So do not double precipitately where you might get doubled back, unless you have a good chance to win a gammon.
