I would love to see the other side of all of this correspondence. It would be fascinating to find out how (if at all) people responded to what Dick is trying to explain to them.
This appears to be a third letter to Malcolm Edwards. Dick references a January 30th letter that wasn’t included here. He expands on something he must have brought up in the second letter about some kind of structure that surrounds people and allows only them to receive a certain signal. These disinhibiting signals are created by the combination of several otherwise innocuous things like signage or advertising which trigger the neural firing of someone primed to receive it. The Creator is the one who programmed this whole signaling system in a deterministic way, and living creatures are the only things real in this universe. Everything else is just artificial props and scenery.