The Falling Dream

In this dream, I am falling, not from any specific place or down to any specific location, but definitely falling and scary. And I am totally powerless to stop the fall. Invariably, when I land, I am not injured. There is no pain. In fact, although I have hit bottom, it feels like a soft landing, and the dream always ends as soon as I land. The soft landing is especially curious because in any fall onto almost any surface you generally end up with some kind of disaster. What would explain all these details of this dream? I discovered the physical cause of this dream when, one day, I woke up immediately after the dream and realized that my knees had fallen down. I was sleeping on my back with both of my knees tucked up and, as I straightened my legs, the weight of the bed cover and my legs caused my feet to slip out and the knees to fall. This falling knee caused my brain to create the falling dream! At first, this was just a hypothetical explanation, and a patently silly one at that. Why couldn't my brain figure out that my knees are falling? But once the hypothesis was made, I was able to test it every time I had the dream (over a span of several years), and I succeeded in verifying it several times. Upon awakening, I could distinctly remember that my knees had just fallen down. The fact that the knees fall onto the soft bed explains the soft landing and since nothing happens after that, the dream ends. Why am I powerless to stop the knees from falling? As shown repeatedly below, when asleep, we sometimes have very little control over our muscles. Not only that, the sleeping brain can't even figure out the simple fact that the knee is falling. In addition, it concocts what should normally be an unbelievable scenario of a fall, and I actually end up believing it. This last part is the most preposterous, because I am effectively fooling myself!