Reality is that which, when you stop believing in it, doesn't go away. - Philip K. Dick

"Imagine a brain floating in a tank with millions and millions of electrodes attached to specific nerve centers. Now imagine these electrodes being selectively stimulated by a computer to cause the brain to believe that it was walking down Hollywood Boulevard chomping on a hamburger and checking out the chicks. Now, if there was a technological foul-up, or if the tapes got jumbled, the brain would suddenly see Jesus Christ pass by down Hollywood Boulevard on his way to Golgotha, pursued by a crowd of angry people, being whipped along by seven Roman Centurions. The brain would say, "Now hold on there!" And suddenly the entire image would go "pop" and disappear. I've always had this funny feeling about reality. It just seems very feeble to me sometimes. It doesn't seem to have the substantiality that it's suppose to have."

“Isn’t there any way—” He broke off. Can’t the past be altered? he asked himself. Evidently not. Cause and effect work in only one direction, and change is real. So what’s gone is gone, and I might as well get out of here.

The old man said, ‘You will be required to do wrong no matter where you go. It is the basic condition of life, to be required to violate your own identity. At some time, every creature which lives must do so. It is the ultimate shadow, the defeat of creation; this is the curse at work, the curse that feeds on all life. Everywhere in the universe.