“Reverse the polarity of the neutron flow” was a bit of generic bafflegab developed during the Pertwee era. Legend has it that Pertwee came up with it himself because he had difficulty remembering some of the more bizarre bits of technobabble, and had quite pragmatically realized that it didn’t actually matter what he said as long as it sounded important and was delivered with confidence. He used the line often enough that it stuck, and it is now firmly entrenched in Who lore as the ultimate solution to any technological problem where the actual mechanism for solving the problem doesn’t actually matter to the script.

I knew I should have mentioned the tumbling bit, because it had occurred to me as well, and I chalked it up to limitations of simulating zero-G in front of a green screen.

I remember some of the other things you mentioned; maybe those are part of the reason Tom Baker is still my favorite Doctor.

Doctor Who has always had a generally skeptical attitude, and despite the often bizarre settings, haphazard physics (the Fourth Doctor once repeated the old chestnut about bumblebees not being able to fly), and often insufficient research, there has always been a very strong theme of critical thinking running through it.

Magic always took a particular beating on the series. It was usually revealed to be either trickery or merely a form of technology or alien race using physical properties which people just didn’t know about. Clarke’s Law, though never (to my recollection) directly quoted, underlay many episodes. You do see a lot of stuff like hypnotism presented like a 19th Century imaginative fiction novel or a 1950s B movie, but there is an underlying assumption that it’s not magic but rather something that simply hasn’t been discovered by humans as of the latter part of the 20th Century.

One of my favorite bits about astrology comes from “Masque of Mandragora”, a Fourth Doctor story, quoted (and mangled) from memory (for instance, I can’t remember exactly what it was that Hieronymus asked):
HIERONYMUS: What does it mean when the moon is in the house of the Ram and Jupiter is ascendant?
DOCTOR: This is all a great waste of time.
COUNT FEDERICO: Answer him.
DOCTOR: Well, it depends, doesn’t it?
HIERONYMUS: On what?
DOCTOR: On whether the cock crows three times before daybreak and a hen lays three addled eggs.
HIERONYMUS: What school of philosophy is this?
DOCTOR: I can easily teach him. All it takes is a cunning imagination and a glib tongue.

Other good lines from the series:
“Nothing is inexplicable: only unexplained.”
(Fourth Doctor, but I don’t remember which episode offhand. I like to quote this one, though.)

“The very powerful and the very stupid have one thing in common: they don’t alter their views to fit the facts, they alter the facts to fit the views, which can be very uncomfortable if you happen to be one of the facts which needs altering.”
(The Doctor discussing how the evil computer in “Face of Evil” planned to kill him because he could prove that the elaborate fiction it had concocted was all a lie.)

“Allow me to congratulate you, sir. You have the most totally closed mind I have ever encountered.”
(Third Doctor, to someone who absolutely refused to accept evidence)

“We start getting proof and we stop believing.”
“With this proof, we don’t have to believe.”
(Two members of the Sevateem, Leela’s tribe, discovering the truth of their “god” and the Tesh, their sworn enemies and undergoing a religious epiphany.)

“Never guess. Unless you have to. There’s enough uncertainty in the universe as it is.”
(From Logopolis, this one was also sort of a nod to the themes of chaos and entropy running through the episode.)

I did see an interview on Doctor Who Confidential that makes me a little more grateful about what kind of stuff gets into episodes. One of the producers was commenting on what I thought was one of the better examples of good physics in DW: Peter Davidson’s Doctor is attempting to get from a ship in space to the TARDIS and gets stuck in the middle (I think because somebody pulled him to a stop with a lanyard and then cut the lanyard). He throws a cricket ball against the ship and then catches it on the rebound to provide enough impulse to move him along before he runs out of air.

The producer says he thought that such a thing was *totally impossible* (although he didn’t elaborate). If these are the guys that are making content decisions, be glad for what you get.