"Certain themes appear with surprising consistency in Dick’s fiction. They crop up in the early short stories, called by some critics, including Kim Stanley Robinson, Dick’s “apprentice” fiction. They appear in the novels of Dick’s most productive period, the 1960s. And they are a part of the last novels, the VALIS trilogy and The Transmigration of Timothy Archer—written when Dick was, according to Eric Rabkin and others, insane. These themes fall into three inter-related categories: metaphysics, religion, and politics. The first concerns perception and the world, and the individual’s interaction with both. The second, the moralities of creator/creation relationships. The third, relationships between individuals; by extension, between individuals and political systems. From these, and from their interactions, come all other political points presented in Dick’s fiction."
Barlow, Aaron. How Much Does Chaos Scare You?: Politics, Religion, and Philosophy in the Fiction of Philip K. Dick. Lulu. com, 2005.