Question: What exactly was Scotty's reason as to why giving the Company boss the formula for the one inch glass wouldn't alter the future? He gave a brief response, but I honestly can't think of any reason why it wouldn't do any future damage.
Chosen answer: Scotty says "Why? How do you know he didn't invent the thing!" If the man was in fact the inventor, this would only cause a slight causality loop problem - he "invents" it because they gave it to him, but they only know it because he "invented" it. However, since Sulu said earlier in the movie that it was about 150 years too early for transparent aluminum, it would seem they do know this, so it wasn't a smart thing to do. Of course, the real flaw in the plot is that they need the tank to be transparent at all.
Answer: The crew is resigned to the fact that their mission forces them to alter history in some fashion or another. McCoy just wants to acknowledge the gravity of their actions before they go ahead and do it, and Scotty's response is a cheeky way of reassuring him, "Hey, maybe it won't be that bad."
Question: In a few scenes in the film, the characters mention how people of the 20th century still use money. Key word: still. How is the process of currency different in the 23rd century compared to the present?
Answer: The United Federation of Planets uses the credit. Its a purely electronic form of money. Necessities and luxuries both are simple and cheap to produce with the Federation's advanced technology, and humanity has matured to the point that accumulating wealth is considered vulgar. Furthering the common good or the advancement of humanity is the real status symbol in the 23rd and 24th century. These conditions result in a society with very little need for money. Citizens are paid, but since the technology built into a place of business (or starship) or home supplies all basic needs for free, most people spend money only on exotic products that aren't commonly manufactured, like art or handmade foods.
Question: Kirk and crew deliberately disclose crucial technological secrets, extend the life of a random stranger, deliver future technology to a primitive military power, abduct a cetacean biologist, and actually contribute to the extinction of a species during their brief stay in 20th Century San Francisco. Specifically: Scotty reveals the secret of Transparent Aluminum 150 years too early; McCoy arbitrarily uses 23rd Century medicine to cure a seriously ill 20th Century woman; and Kirk chooses to remove Gillian from the 20th Century. Perhaps most importantly, Chekov leaves behind a Starfleet Communicator and a Type 2 Phaser in the hands of the U.S. Navy (who would undoubtedly dissect the devices and try to exploit the technology a couple of centuries too soon). Beyond all that, Kirk and crew abduct two breeding humpback whales, one of which is pregnant, and that certainly contributes to humpback extinction in the 21st Century. Given what we think we know about disrupting linear time continuity (many instances are cited in Star Trek canon), how did Kirk and crew return to anything even resembling their own timeline after such blatant and deliberate interference in Earth history?
Chosen answer: This question has been answered a number of times by various individuals, all saying pretty much the same thing. The answers have been most satisfactory given the question revolves around a fictitious situation and the answer (s) need to be accepted as complete for this purpose. Any dispute or non-acceptance should be addressed in a Star Trek forum. Any ignoring of the Prime Directive was done to save the future of Earth, as the probe would have wiped out all life on Earth. Essentially, nothing that was done in the past resulted in major changes that would make Earth 300 years later appear any different, and no major futuristic technologies were revealed. The major one, Chekov's communicator and phaser being left behind did not result in anybody learning secrets. In the film, the phaser didn't function because of the radiation. It's presumed then the radiation permanently damaged the equipment so it appeared to be nothing but a toy or prop. However, in the novel "The Eugenics Wars: The Rise and Fall of Khan Noonien Singh", Roberta Lincoln was sent by Gary Seven to recover the items from Area 51 before any secrets were learned (and as stated before, additional corrections to Earth's timeline could have been done that aren't addressed in the film.) The subsequent loss of a suspicious "ruskie" would have hardly affected the era that was already in the midst of the Cold War. McCoy even questions that giving Dr. Nichols the formula for transparent aluminum could alter history to which Scotty replies what if Dr. Nichols is the one who invents it, to which McCoy agrees (in a later novel it is reveled that Scotty already knew Dr. Nichols invented transparent aluminum, so history was not changed.) The miraculous recovery of the old lady (growing a new kidney) was done by a pill so that any examination of her would not reveal the futuristic method involved. She would be a bewilderment to the medical community at best, and most likely misdiagnosis would be to blame. And just because she got a new kidney does not mean her life would have been extended, she could have died some other way in both timelines. And as stated before, Gillian simply wasn't vital to Earth's history. She could have contributed nothing of importance to society and died alone and childless. And a missing pair of breeding Humpbacks would hardly affect the extinction of their species, however in the future, they are already extinct, so little changes would occur. As for any questions about people seeing the Klingon ship in the past, who would believe them? People have long been claiming to see spaceships and aliens to little or no avail, so why would anyone believe a handful of people who said they saw aliens in a spaceship steal 2 whales? However, as with many time travel situations in films and novels, it's possible the events of the 23rd century as they appear in the beginning of the film are a result of Kirk and company's actions in the 20th century since the events already occurred even though Kirk and company had not yet done it themselves (this is where a discussion forum on the film would be advised, or a discussion forum on the theories of time travel).
Possibly the most convoluted and poorly-reasoned series of answers I've seen on this site. So far.
I think they're pretty logical actually.
I think your opinion would be in the minority. There is nothing exceptionally convoluted, nor poorly reasoned in the response.
Answer: They were extraordinarily lucky. The crew quite often defies all odds and encounters literal miracles. For a period of time this even happened on a roughly weekly basis.
Question: When Kirk and McCoy try to rescue Chekov at Mercy Hospital, Kirk removes the 20th Century medical team into an adjacent room and uses his phaser to instantly fuse the metal door lock. The medical team cannot directly see Kirk do this, as they are visibly several feet away on the other side of the door. It's also safe to say that the medical team has never seen a phaser and can't comprehend its function or capabilities. As Kirk turns away from the door to rejoin McCoy, the trapped medical team only then rushes up to the door, and the trauma surgeon exclaims, "He melted the lock!" However, it seems that you'd have to laboriously dismantle the doorknob to determine that the lock's internal components were fused. So, how did a 20th Century surgeon deduce at a glance that Kirk had somehow melted the lock?
Answer: The lock, and the area around it, would have become hot as a result of melting the lock. The hospital staff would then jump to the conclusion that the lock was melted. The real reason they mention it, however, is so the audience knows what he did to the lock.
But you would think, if the doorknob was still searing hot two seconds after being fused, that the first thing out of the surgeon's mouth would be a scream of pain, rather than "He melted the lock!"
Answer: The doctors were watching through the window the entire time. There was a visible red laser beam from the phaser, culminating with a puff of smoke or vapor emanating from the knob. It wouldn't be a huge leap for anyone to surmise that the knob had likely been melted.
Try watching the scene. No doctors are looking through the window when Kirk phasers the door lock.
Answer: Or perhaps the part of lock on the doctors' side is visibility melted.
Answer: The knob would have been super-heated by the phaser blast. Enough that it could be felt without touching, and he simply could have come to the conclusion that a metal object that hot would likely have its internal components melted without a systematic analysis of the doorknob. He's also a surgeon and needs his hands. He wouldn't last long at the job if he was someone who went around putting his hand on glowing-hot doorknobs.
He could've also been guessing as it appears he tries opening the door. Why they don't break the glass is beyond me, but that's a character mistake, and not up for debate here.
Question: Why does the probe even wish to talk to humpback whales?
Answer: It's stated by Spock in the movie, even if he is just speculating. He mentions that humans are not the only intelligent special on Earth, and that it's human arrogance to assume that the probe's signal, "Must be meant for man." The point is, the aliens were communicating with the whales, and when that communication stopped, they sent the probe to find out why.
Answer: There is a hypothesis by Spock that the probe was perhaps sent to find out why they didn't hear the whale song any more.
Answer: Wouldn't you if you could?
Question: In the scene where the crew exits the ship via the retractable doorway and gets seen by the garbage men, they had enough power to beam out but decided to walk out regardless, and risk being seen. Yet every other time they beamed in and out of the ship, so why not that particular time? Furthermore, why would the garbage men dismiss it so easily and not report it or return again later.
Chosen answer: There's no reason given, but it might have something to do with the fact that all of them are leaving the ship at the same time. It may be necessary for someone to remain on board to beam them in and out, as opposed to manually opening and closing the hatch from the outside. Being as this is a Klingon ship, the technology does not exactly work the same as their own. As to the garbage collectors, they did not report seeing anything for fear of no one believing them, being ridiculed, and possibly losing their jobs. They may also simply not believe what they are seeing.
Answer: They only give him a schematic of the molecule. The man even says, "It would take years to decipher the matrix", or something like that.