Philip K. Dick's famous speech, available online here.
"Unceasingly we are bombarded with pseudo-realities manufactured by very sophisticated people using very sophisticated electronic mechanisms. I do not distrust their motives; I distrust their power. They have a lot of it. And it is an astonishing power: that of creating whole universes, universes of the mind. I ought to know. I do the same thing." Ah, if only that power were as potent as Dick assumes! The key is not the creation of pseudo-realities, nor even in their sophistication, but in getting people to pay attention them. This, I suppose, is the key question of the incipient Internet Age: being heard. The significant figures will not be those with the greatest aesthetic or literary or intellectual talent, but those best able to attract the attention of a critical mass of people. Everything else will become secondary to that.
"Science Fiction writers, I am sorry to say, really do not know anything. We can't talk about science because our knowledge of it is limited and unofficial, and usually our fiction is dreadful." Fair enough.
"Reality is that which, when you stop believing in it, doesn't go away." One of PKD's most famous utterances, this; but a problematic one nonetheless. It works for, let's say, furniture: you'll still bark your shin upon the coffee table whether or not you believe it is there. But it's hard to see how it can be true of things like love, honour, truth, meaning and (crucially) belief itself.