from here.
In my writing I got so interested in fakes that I finally came up with the concept of fake fakes. For example, in Disneyland there are fake birds worked by electric motors which emit caws and shrieks as you pass by them. Suppose some night all of us sneaked into the park with real birds and substituted them for the artificial ones. Imagine the horror the Disneyland officials would feel when they discovered the cruel hoax. Real birds! And perhaps someday even real hippos and lions. Consternation. The park being cunningly transmuted from the unreal to the real, by sinister forces. For instance, suppose the Matterhorn turned into a genuine snow-covered mountain? What if the entire place, by a miracle of God’s power and wisdom, was changed, in a moment, in the blink of an eye, into something incorruptible? They would have to close down.
In Plato’s Timaeus, God does not create the universe, as does the Christian God; He simply finds it one day. It is in a state of total chaos. God sets to work to transform the chaos into order. That idea appeals to me, and I have adapted it to fit my own intellectual needs: What if our universe started out as not quite real, a sort of illusion, as the Hindu religion teaches, and God, out of love and kindness for us, is slowly transmuting it, slowly and secretly, into something real?
We would not be aware of this transformation, since we were not aware that our world was an illusion in the first place. This technically is a Gnostic idea. Gnosticism is a religion which embraced Jews, Christians, and pagans for several centuries. I have been accused of holding Gnostic ideas. I guess I do. At one time I would have been burned. But some of their ideas intrigue me. One time, when I was researching Gnosticism in the Britannica, I came across mention of a Gnostic codex called The Unreal God and the Aspects of His Nonexistent Universe, an idea which reduced me to helpless laughter. What kind of person would write about something that he knows doesn’t exist, and how can something that doesn’t exist have aspects? But then I realized that I’d been writing about these matters for over twenty-five years. I guess there is a lot of latitude in what you can say when writing about a topic that does not exist. A friend of mine once published a book called Snakes of Hawaii. A number of libraries wrote him ordering copies. Well, there are no snakes in Hawaii. All the pages of his book were blank.

Of course, in science fiction no pretense is made that the worlds described are real. This is why we call it fiction. The reader is warned in advance not to believe what he is about to read. Equally true, the visitors to Disneyland understand that Mr. Toad does not really exist and that the pirates are animated by motors and servo-assist mechanisms, relays and electronic circuits. So no deception is taking place.

And yet the strange thing is, in some way, some real way, much of what appears under the title “science fiction” is true. It may not be literally true, I suppose. We have not really been invaded by creatures from another star system, as depicted in Close Encounters of the Third Kind. The producers of that film never intended for us to believe it. Or did they?

And, more important, if they did intend to state this, is it actually true? That is the issue: not, Does the author or producer believe it, but—Is it true? Because, quite by accident, in the pursuit of a good yarn, a science fiction author or producer or scriptwriter might stumble onto the truth… and only later on realize it.

The basic tool for the manipulation of reality is the manipulation of words. If you can control the meaning of words, you can control the people who must use the words. George Orwell made this clear in his novel 1984. But another way to control the minds of people is to control their perceptions. If you can get them to see the world as you do, they will think as you do. Comprehension follows perception. How do you get them to see the reality you see? After all, it is only one reality out of many. Images are a basic constituent: pictures. This is why the power of TV to influence young minds is so staggeringly vast. Words and pictures are synchronized. The possibility of total control of the viewer exists, especially the young viewer. TV viewing is a kind of sleep-learning. An EEG of a person watching TV shows that after about half an hour the brain decides that nothing is happening, and it goes into a hypnoidal twilight state, emitting alpha waves. This is because there is such little eye motion. In addition, much of the information is graphic and therefore passes into the right hemisphere of the brain, rather than being processed by the left, where the conscious personality is located. Recent experiments indicate that much of what we see on the TV screen is received on a subliminal basis. We only imagine that we consciously see what is there. The bulk of the messages elude our attention; literally, after a few hours of TV watching, we do not know what we have seen. Our memories are spurious, like our memories of dreams; the blank are filled in retrospectively. And falsified. We have participated unknowingly in the creation of a spurious reality, and then we have obligingly fed it to ourselves. We have colluded in our own doom.
from here.
And—and I say this as a professional fiction writer—the producers, scriptwriters, and directors who create these video/audio worlds do not know how much of their content is true. In other words, they are victims of their own product, along with us. Speaking for myself, I do not know how much of my writing is true, or which parts (if any) are true. This is a potentially lethal situation. We have fiction mimicking truth, and truth mimicking fiction. We have a dangerous overlap, a dangerous blur. And in all probability it is not deliberate. In fact, that is part of the problem. You cannot legislate an author into correctly labeling his product, like a can of pudding whose ingredients are listed on the label… you cannot compel him to declare what part is true and what isn’t if he himself does not know.

We want to thank Philip K. Dick, author of The Three Stigmata Of Palmer Eldritch and The Man In The High Castle amongst many other novels, for sticking it to reality and taking time out of his busy afterlife to share with us another excerpt from his 1978 speech “How To Build A Reality That Doesn’t Fall Apart Two Days Later.” It also appears as the introduction to his 1985 short story collection, I Hope I Shall Arrive Soon. The first excerpt he shared with us is here, and…
…you have to love that PKD fans are called dickheads.

For the sake of truth, we can tell you that Mr. Dick will probably return with another excerpt for us in the next few days. But until then…
Jonathan Lethem being interviewed about PKD.