Entities should not be multiplied beyond necessity - Occam's Razor
What Occam meant by this, is that if you encounter something that has multiple possibilities, the least complex is also the most likely.
To drive this point home let me give you an example. Today I saw that halfway through the morning the door to my office was missing it's core cylinder. This is the part you would normally put your key in. Near the end of the afternoon it was back. How could this have happened? I was not alarmed. I simply applied Occam's Razor to the problem, with a liberal amount of shaving cream of course.
I figured that they aren't trying to lock me out of my office. No. More likely the key cylinder fell out sometime today unnoticed by me or anyone else. It sat on the ground until someone with a good pair of running shoes happened by. Those type of shoes with the really high insoles for support. This person had just been out for a jog. This person more than likely had just stepped on some gum and, unbeknownst to them, picked up my key cylinder.
During their jog they remembered something. And came by my neighbors office who is their manager. My neighbor was not in. This person then roamed around the office looking for my neighbor who had forgotten to sign this persons vacation form. Today being the last day before they left for their vacation, they needed this signature quite badly. After an hour or so this person gave up. They resolved that there was little they could do beside weep and kick things. They then kicked the door jam in the break room and dislodged my key cylinder. They didn't hear it fall due to the little screaming voices in their heads telling them about how lonely Tahiti would be without them.
When afterwords the office shuffler happened by and accidentally shuffled my key cylinder right past a friend. The shuffler and shufflers friend then engaged in conversation for twenty minutes or so about soap and it's less practical uses. As they were about to leave, the maintenance tech happened by.
He noticed my key cylinder and due to his strong work ethic, checked every door in the office for a missing cylinder. He found mine empty and replaced it. Additionally he left a sticky note for me explaining the whole affair. As fate wold have it, just as he turned around a gust of wind blew up the note and it stuck to the back of his pants. The note was only freed as he walked out the back door. It is now sitting in the top of an oak tree where it will live out the rest of it's days quite peacefully.
So as you can see, it was a perfectly normal thing to happen.