Six hours later, she came back to the hangout with her head down and opened the door..... “Did you lose your key? Let’s use the spare key to unlock it.” It was a very mediocre proposal, but the owner of the locked locker hadn’t made a spare key. Someone asked her: why didn’t you make a spare key? She replied: If I don’t lose the key, nothing will matter, so I won’t make a spare key. Can we handle multiple things at once? We cannot perceive multiple things at once. We can only categorize multiple things. Categorization is purely conceptual and not a practical matter. Therefore, the object that we can perceive must always be alone. Her inevitable failure doesn’t stop there. She traveled with the key to the entrance to this hangout. One morning, a few people gathered in front of the hangout and someone called her. She had already traveled about 500 kilometers driving her car. Why are we able to deal with two or more things at the same time in our daily...