Acts A and B are exactly similar in their universal properties if they have the same universal properties -- so that A has every universal property that B has, and vice versa.
Acts A and B are exactly similar in their universal properties if they have the same universal properties -- so that A has every universal property that B has, and vice versa.
In the actual world, no two acts are exactly similar in all their universal properties. However, the idea of exact similarity can usefully be applied to hypothetical cases. To test our impartiality, we can ask how we react to a hypothetical case in which we imagine ourselves in the exact place of the other person on the receiving end of the action.
Acts A and B are exactly similar in their universal properties if they have the same universal properties -- so that A has every universal property that B has, and vice versa.