Simplify? Let me try. In school days, we are taught that if there are four animals in a room and you add two more, the total will be six. That is logic. But behind this logic, there are underlying assumptions. Now, if somebody tells you, there are four rats in the room and if you add two more cats in the room, how many animals in total exist in the room now? The answer will depend upon assumption. If you just use your mathematical brain, you will say six animals. If you use your human brain, you will say two animals. Why two animals? Because the two cats will eat the four rats in no time.