WMG / Dirk Gently

Gusty Winds in Salmon of Doubt is an incarnation of Schroedinger's Cat
Considering that it's a cat that's half alive (specifically, the front half), we don't know if the back half is still alive, and he passes a sign reading "GUSTY WINDS MAY EXIST"...

In Salmon of Doubt, a future version of Dirk is orchestrating the first few chapters.
  • The encounter with the owner of Gusty Winds would not, as he says to Kate, be possible unless someone pretty much had the information in the notebook he is carrying.
  • He called his own number and he answered.
  • The pizza place says only he has ordered that pizza.
  • The actor "lurched into sight" (presumably pushed?) just after the postman provides a memorable future reference point.
  • The handwriting on the note is "oddly familiar."
  • Someone took money out of his account through an ATM. He can't see how anyone could do that unless they had his card (which he still has) and knew his PIN.
  • And, of course, the book was supposed to be about "the emergent properties of complex systems," i.e. systems that are recursive.

Professor Chronitis is a Time Lord, and his time machine is his TARDIS.
Yeah, that's right. This WMG was actually justified once. The end times are upon us.
  • Confirmed, since Shada, which featured Professor Chronitis as a Time Lord in it, is canon in the Whoniverse.
  • Bear in mind Douglas Adams did write several episodes of Doctor Who and in fact originally intended Tom Baker to be facing the Krikkitmen.

All life in the universe is a result of a stable time loop.
Life on Earth started because of an accident caused by another intelligent life form. Time travel is also possible in the Dirk Gently universe. What more evidence do you need?

Dave, from the first chapter of Salmon of Doubt, is a kangaroo.
It's mentioned that the human race is extinct, and that kangaroos are being taught to speak. Perhaps the "heavily armed kangaroos" from the description brought about the death of the human race, and now rule the world?

Salmon of Doubt could have seen Dirk saving the Hitchhikers Guide cast at the end of Mostly Harmless.
The story follows on quite closely from the end of the previous book, placing it at the end of the 1980s at a time seemingly before Mostly Harmless (or at least the bits set in what seems to be early 1990s Earth). The mysterious source paying Dirk could be trying to enlist his assistance in trying to defeat the Guide MK 2 and it's temporal reverse engineering (possibly the Campaign For Real Time from Life, the Universe and Everything). After all Dirk knows about both time travel and jumping into the dimension of the Norse Gods. In the Hitchhikers universe we learn about the "higher dimensions" in Life, the Universe and Everything. We also know that their supposedly unpleasant occupants would be done away with if anyone could work out how to fire missiles "at right angles to reality", making the whole Brockian Ultra Cricket bit turn from a silly aside to a major Foreshadowing. Douglas Adams expressed an interest in 'fixing' the Downer Ending of Mostly Harmless, and a possible crossover between Hitchhikers and Dirk Gently, and setting the book in the same time frame as Mostly Harmless would have allowed the characters from Dirk's Earth to save the other Earths. However in his final TV interview he also noted that some of the ideas in Salmon of Doubt might instead be used for a Hitchhiker book, possibly indicating that he'd given up the crossover idea.