|You know it makes sense|
"The Savage Curtain" (TOS)
This is the one where the Enterprise encounters Abraham Lincoln. Kirk and Spock beam down and meet up with Surak. It turns out that some rather interesting rock-aliens want to understand the humans' concepts of "good" and "evil" and have arranged a fight between four good characters and four historic villains. Kirk and Spock at first decline to fight, so the alien arranges that the Enterprise will be destroyed unless they beat the others.
One of the common objections to the episode is a simple chronological error. One of the villains is Kahless, the founder of Klingon warrior culture. In most of Star Trek he is a revered figure, so why is he a villain? Of course, these are not the real people but projections from the humans' expectations, so you can say that this is Kirk's anti-Klingon prejudice. But the real answer is that the positive view of honourable Klingons starts with TNG. The TOS Klingons are militaristic villains. We don't really know much about them, and we do occasionally glimpse things from their point of view, in which the Federation is the villain. But this is the first time Kahless appears. It's TNG and its successors that altered his significance. If you insist on a consistent "canon" then the "Kirk's-prejudice" explanation will do, but it is not reasonable to criticize the writers because their version isn't consistent with a later revision.
Another criticism is that Kirk is strangely credulous about Lincoln, when he ought to know this must be some sort of trick. But this is raised in the episode, with McCoy and others warning him. In particular McCoy notes that it seems quite a coincidence they created a replica of one of Kirk's personal heroes, and Kirk is the one who will be deciding whether to beam down. Kirk tells them that he knows it an illusion, but a Captain's Log entry seems to suggest that he finds it hard to resist the illusion.
It has got its faults, certainly. However, there are some very interesting aspects to the episode.
Possibly the most important is Surak. This is the first time we encounter him, and we learn a lot more about the origins of Vulcan thought. Spock does not believe it is Surak, of course. But, as with Kirk, he can't help behaving as if he did. When Surak refers to the emotion he saw in Spock's face, Spock apologizes. Barry Atwater's performance as Surak is striking. He has presence, he conveys intellectual and moral strength—and a touch of arrogance, the necessary self-confidence of the reforming leader who knows he has the answers. He tells Kirk of the devastating wars of the Vulcan past, and of how some went to the other side to talk peace. "The first were killed, but others followed."
Surak goes, to talk peace, and is killed. Lincoln, trying to rescue him, is also killed.
Kirk and Spock eventually prevail. The alien is a bit disappointed. Evil runs away, it notes, but in general good and evil seem to use the same methods and aim at the same results. Kirk ripostes that the others were fighting for power (which they had been promised) while he and Spock were fighting for their shipmates' lives. The alien says "I perceive", but it sounds like "Yeah, whatever."
At the end there is an interesting exchange between Kirk and Spock. Kirk comments how real they seemed, especially Lincoln (who had, we learnt earlier, always been one of his heroes). Spock points out that since the illusions were drawn from their own thoughts, they were inevitably just what they expected. This is worth thinking about. We construct our mental images of heroes, both present-day and historical, according to what we know but also according to what appeals to us.
"Let That Be Your Last Battlefield" (TOS)
This is the one with the two aliens, both of whom are black on one side and white on the other, but with opposite ways round. The one with white on the left thinks the one with white on the right is obviously inferior, or is it the other way round? Of course, it's an allegory for racism and civil rights. One of the aliens (Bele) is trying to arrest the other (Lokai) for alleged terrorism.
Like many Star Trek episodes, this one raises issues. As well as the issues which were intended, you sometimes find that an episode raises issues for discussion in a way that wasn't intended. You could call them "yes, but" episodes.
The first criticism of the half-black/half-white allegory is that it's crude and over-the-top. I don't think that is necessarily true. The sheer ludicrousness of colour prejudice was a point worth making at that time. However, is racism just about prejudice of that sort? Even then, that would have been a limited view.
However, the episode doesn't limit itself to colour prejudice. The conflict seems to be between two different groups, one (represented by Bele) with more power. Here we come to the aspect that for a modern viewer is likely to raise questions. The episode presents the two sides as in some sense symmetrical, both guilty of "hate". But if Lokai's people are in fact oppressed, regarding the conflict as symmetrical is a false equivalence. Bele himself says at one point that Lokai's kind are now "penned in... into little districts", which definitely implies this. A present-day viewer tends to side, prima facie, with Lokai, rather than see them as mirror-images. Lokai may not be an appealing character, but we are less likely to find that so crucial—resistance leaders are not judged by their cuddliness. One could say, in response, that Lokai is accused of being a terrorist. (It should be noted, though, that we never really know how much of what either says is true.) More significantly, the symmetry is connected in terms of narrative with the absurd left/right basis of the aliens' racism; perhaps it is the visual inspiration which was driving the writing?
So in the end, perhaps what makes this episode most interesting is not its denunciation of prejudice, but the way in which its attempt to denounce prejudice doesn't entirely work. Thinking about why the analysis seems limited or not quite right can be a useful exercise.
Some other points. One criticism is an occasion for a piece of trivia. One of the aliens arrives on an invisible spaceship. Why? We never hear any more about it. The actual reason seems to be that there was no money left.
The episode is talky, but the talk is interesting. The crew treat the aliens with courtesy when they aren't giving trouble, and try to suggest alternative ways of thinking. Spock tells Bele about how Vulcan overcame its violent past. Bele and Lokai sound relatively reasonable when apart, but when they confront each other they not only hurl abuse at each other but reveal their contempt of the Enterprise crew who won't see things their way.
It's also very theatrical in places, especially the end, when they arrive at the planet and it is revealed that both races have been completely destroyed by the conflict. Kirk is actually begging them to abandon the fight and enjoy what's left of their lives. "You're welcome to live with us," he says. But they are beyond hearing.
The episode is also notable for the sequence in which Kirk threatens to destroy the ship unless Bele restores control to him. This is sometimes criticized as a digression. But what a digression! No one ever forgets it. In Star Trek 3, when they really do destroy the Enterprise, the same self-destruct codes are used. Many people could recite them from memory. In TNG, codes are long random strings, which makes sense from a logical point of view. But TOS is all about the story, not seriously pretending to be scientific, so the final code is "Zero, Zero, Zero, Destruct, Zero." Hardly a secure code, but which of the two makes your spine tingle?
The scene is referenced in The Big Bang Theory when Leonard's girlfriend Priya, a lawyer, undoes the Roommate Agreement. So Sheldon sets his laptop on a one-minute countdown to sending an email to Priya's parents in India, who would most definitely not approve of her relationship—unless Leonard signs the new Roommate Agreement. "You may have gone to Cambridge," says Sheldon to Priya, "but I'm an honorary graduate of Starfleet Academy."
"Spectre of the Gun" (TOS)
Some aliens are going to kill Kirk and the others in a simulation of the Old West, more specifically the Gunfight at the O.K. Corral. Kirk and his companions try all the rational options, such as negotiation or withdrawal, but nothing works. They build a knock-out bomb, but when they test it (Kirk insists), it doesn't work. Eventually Spock realizes it's all mental projection. Here the episode becomes quite sophisticated and raises issues from the philosophy of science. Spock doesn't just suddenly see that it's all mental, he reaches this conclusion logically.
Spock presents his argument very clearly, in terms of "uniformitarianism", the principle that the physical laws of the universe are the same everywhere. Without this assumption, science would be impossible. A scientist carries out an experiment in a lab, and we believe that the same thing would happen in a distant star. Unless we make this assumption then our experiments could tell us nothing about what is happening in other times or places. However, Spock points out, what they have experienced does not match the physical universe. The conclusion, therefore, is that this isn't the physical universe. Spock mind-melds with them to give them certainty of the unreality, and the bullets cannot now harm them.
This is some serious food for thought. There are in fact other logical possibilities. If what you experience isn't according to what you think the physical laws are, it may be that you need to revise your laws a bit. This is one way science advances. However we would normally only consider that after a series of observations. Another logical possibility is that the event is supernatural, but that is not normally considered an option in Star Trek.
Incidentally, it has been questioned whether the uniformitarian principle is really completely secure. But it's the best we've got. Philosophy of science is a very interesting subject. Try the book in the Very Short Introduction series.
The episode is visually memorable. The setting is positively surreal. The sky is red. Rather than a complete town, they are just walking around in a set of false fronts, the bits and pieces necessary for the events. You could say this eventually makes sense in terms of the whole thing being in the mind, but I think it is most effective just to accept it. The world they have entered is windswept, empty, not all there.
Not only is the eventual solution interesting in itself, it's symbolic. "The only thing we have to fear is fear itself" is the moral. The crew calmly face the onslaught. When the bullets fail to have any effect, Kirk moves in for a fist-fight (of course). He beats Wyatt Earp (who, significantly, does look afraid) but doesn't kill him, which impresses the aliens enough that they decide to welcome the Enterprise after all.
"The Alternative Factor" (TOS)
The Enterprise is orbiting an uninhabited planet when there is an inexplicable momentary event affecting the galaxy—apparent momentary nonexistence—centred on the planet. They find that a human being (with a miniature ship) has appeared on the planet. He is named Lazarus, and seems crazed, asking Captain Kirk to join him on his "holy cause", to destroy a monstrous being (humanoid in appearance) who can destroy worlds. It should be noted that Lazarus has some truly bizarre facial hair, a thin hanging fringe. What significance this has is never revealed, but it's memorable. At first Lazarus's clams seem nonsense to Kirk, except that it might connect to the strange phenomenon. Later Lazarus says that he and the enemy are time travellers, that he has pursued him across time, and that this planet was destroyed by the enemy. Periodically there is a whirling disorientation, and Lazarus (in photographic negative) seems to be struggling with someone else. Kirk and Spock begin to believe that there are actually two Lazaruses, from alternative universes, and that there is a sort of breach between the universes.
While investigating, Kirk gets too close to Lazarus's ship, and finds himself alone, in what looks like the same place, with an identical ship (it's for inter-universe travel), and an identical but quite uncrazed Lazarus, with identical strange beard. They're in the alternative universe. Lazarus explains that when his people discovered the existence of an identical alternative universe (though one is antimatter) his counterpart went mad, "He could not live knowing that I lived." If they meet outside the "corridor" between the universes it will mean the destruction of everything. Sane Lazarus proposes that Kirk should force his Crazy Lazarus into the corridor, and he will hold him there. They must then destroy the ship, and the corridor will be sealed, saving both universes at the price of sealing them in forever. (Apparently they will live forever in this state.) This is done. As the Enterprise leaves, Kirk ponders on Lazarus's fate, trapped in an eternal fight with a madman. The universe is saved, says Spock. "But what of Lazarus?" asks Kirk.
This raises deep questions. "Is it such a large price to pay for the safety of two universes?" Lazarus asks, but Kirk seems to wonder whether it may be. Would you do what Lazarus does? Should you? Could you? There is a well-known thought experiment about Utilitarianism ethics, the idea that the right choice depends on "the greatest good of the greatest number". Suppose you could achieve Utopia provided that just one innocent child is tortured and never allowed a normal life? This would surely provide a good result for the vast majority, so isn't that the right thing to do? But most people feel that this is not acceptable. This thought experiment was dramatized by Ursula Le Guin in her short story "The Ones Who Walk Away from Omelas", where Omelas is the utopia which somehow requires one miserable child. You may notice that although most people don't feel they could justify living in Omelas, the idea that something "must" be right if it benefits most people is often used in public discussion to justify torture and other immoral actions which supposedly have beneficial results.
The episode's ending isn't quite the same, though. In this case the victim is making the choice, and it can be taken as suggesting the self-sacrifice of Christ. On the other hand, is Kirk justified in helping Lazarus do this to himself?
The episode is memorable. Somehow the image of Lazarus, in that bizarre beard, staggering around the ship ranting about his enemy sticks with you.
Incidentally, it's worth noting that the episode includes as a minor character one Lieutenant Charlene Evans (Janet MacLachlan), a stereotype-busting Black woman in Engineering. (I don't think we learn whether she is African-American, African, etc.)