He wasn't a pathological liar, he was shithouse rat crazy. And he was on amphetamines most of the time; when asked how anyone could be as prolific as he, he told the interviewer, "I'm a science fiction writer with four kids. I take a lot of speed."
Paul Sammon interviewed him while Blade Runner was being shot (less than four years after this essay). PKD hated the production and wanted nothing to do with it. Some days he'd answer the door and give Paul a hug. Some days he'd answer the door and point a .44 magnum at Paul. There was no rhyme or reason between the two days and if questioned, PKD denied it ever happened.
And that's my beef with PKD - all his stories, all his writings, anything he ever did. He had such a tenuous grip on reality that he had no problems writing millions of words in which reality doesn't fucking matter. It's ironic that this speech is somehow titled "How to Build a Universe That Doesn't Fall Apart Two Days Later" - everything PKD ever wrote is as deep as rice paper, a conceit so vulnerable to analysis that the slightest deviation from the face value of the story tears it to shreds. But worse than that, PKD couldn't go more than about 60 pages without forgetting what the tenets of his reality were such that the storyworld rules you started out with got tossed to the side as soon as he found a squirrel to chase.
He's been adapted to cinema more than any other writer or some shit, and fans hold this up as evidence of his brilliance. But the fact of the matter is he had a bunch of interesting ideas and executed them like total shit. Do Androids Dream of Electric Sheep is a total mess. It's unreadable, and it goes on forever, and it has effectively nothing in common with the movie that it's credited for. We Can Remember it For You Wholesale is eight pages worth of short story that never leaves the dentist's office; the sum total of that which makes Total Recall what it is was fabricated out of whole cloth by talented screenwriters. A journey through the works of PKD is a journey through four seasons of Twilight Zone episodes if Rod Serling were a meth-addled narcissist with ADHD.
The pre-Socratic Greek philosopher Parmenides taught that the only things that are real are things which never change... and the pre-Socratic Greek philosopher Heraclitus taught that everything changes. If you superimpose their two views, you get this result: Nothing is real.
Yes, but WHY WOULD YOU DO THAT? What makes that valid? How does multiplying a theory by a theory equal a truth?