Trinity
The relationship between Kirk, Spock, and McCoy is the cornerstone of TOS. They are called archetypes, though perhaps the ancient Rhetoric terms fit best: logos (logical Spock), ethos (ethical Kirk), and pathos (emotional McCoy.) The constant interplay of these qualities makes for fascinating viewing. But these three officers are not only abstractions, but richly developed and dynamic characters. As Spock must learn to control the conflicting aspects of his nature, the others face their own challenges. Together, they overcome much.
James T. Kirk. (William Shatner) He is the ideal Starfleet captain - with a rebellious streak. Loyalty, honor, and courage are important to him, but he's not a "white knight" sort of hero. Rather, like the heroes of Classical mythology, most of his strategies involve cheats or bluffs. He prefers scraping through at any cost to suffering honorable defeat. Compassionate, clever, fun-loving, and inspiring, he can also be selfish, stubborn, intensely serious, and rash. He'll risk his life on a daily basis for Starfleet, but defy them if it means aiding a friend. (Usually Spock.) Kirk stands for the greater good. Most of Starfleet's orders are also righteous, but the captain must make sure the institution's good intentions don't translate into harmful actions.
Jim believes above all that humanoids need both freedom and obstacles to truly live. He liberates populations from such oppressive forces as computer control inReturn of the Archons and The Apple, simulated war in A Taste of Armageddon, gang violence in A Piece of the Action, and decadence in Plato's Stepchildren. The Federation's Prime Directive of Non-Interference is ignored if Kirk is correcting the damage done by earlier interference, or if he deems a civilization stagnant. Yet he can also negotiate with or defeat any enemy, make delivery times, and keep his crew motivated, and so is considered the best captain in the fleet: a wonder since he continually puts admirals and commodores in their place!
Kirk's home-spun values were likely acquired during his youth, farming in Iowa. Always slightly out of place in the far reaches of the galaxy in the 23rd century, Kirk has a fondness for things old-fashioned. He enjoys tales of tall ships and early space exploration. His friends know enough to give him a hardcover book and antique glasses for his birthday in The Wrath of Khan, and they often quote classic literature.
With the ladies, he's a charmer, but prefers walking and talking to heading straight for the bedroom: his reputation as playboy is undeserved. Alas, as captain, Kirk's job is so demanding that committing to a relationship is not a possibility. It's lonely at the top, as he admits under the influence of the Psi-200 virus in The Naked Time. Spock also expresses his sense of isolation here, and the two find comfort in this shared experience.
In fact, Kirk and Spock are friends more because of what they have in common than any "opposite attraction." Both find true homes in Starfleet, which also satisfies their thirst for adventure and novel experience. Neither is fond of rules and regulations, but both take the Federation ideals of justice and equality as personal creeds. Stronger even than their dedication to duty is their loyalty to one another. In the film series, each makes incredible sacrifices for the other, Spock giving his life to save his ship inThe Wrath of Khan, Kirk giving up that same ship, his career, and his son just to have Spock back at his side.
Such friendship does not develop instantly. In the early episodes of TOS the easy-going captain is not sure what to make of his icy first officer. He teases him, they play chess, but the Vulcan remains a mystery. Some understanding is gained in the aforementioned The Naked Time, and also in This Side of Paradise, as Spock is freed of his inhibitions and falls in love with a beautiful scientist; then in Amok Time, which explores Vulcan mating customs and displays the deep bond between Kirk, Spock, and McCoy for the Vulcans as well as viewers.
Throughout the second season and third the pair are inseparable on away missions and on the bridge, seeming to anticipate the other's reactions and decisions - even finishing each other's sentences! Disputes are either on a professional or ideological level, not personal. Kirk puts Spock on trial in The Menagerie and is prepared to carry out the verdict regardless of his feelings. In The Apple, Kirk sees a stagnant people crying to be free, whereas Spock believes they are happy and healthy. In such situations, Kirk does make the call, and Spock knows this is his prerogative. Yet when Kirk's personal feelings begin to influence his judgment, Spock has the right to step in, usually with Dr. McCoy's help. The two curb the captain's irrational behavior in The Conscience of the King and Obsession. It's a rare case that bringsthese two together . . .
Leonard H. McCoy. (Deforest Kelley) can always be relied upon to throw verbal barbs Spock's way. As emotionally expressive as Spock is repressive, McCoy usually has opposing viewpoints to the Vulcan's, and they bicker incessantly.
Though "Bones" would agree he's sensitive and sentimental, his bedside manner would never betray it. Gruff and cantankerous, he has no pity for those patients hurt in careless accidents, and dislikes any disobedience or "attitude." Techology and bureaucracy are also sources of frustration. He often protests whatever wild course of action Jim and Spock are about to take. Once drawn in, however, the doctor does ease up and get in on the fun.
Like Kirk, Bones is enamored with the past. He refers to himself as "an old-fashioned country doctor," and hails from the South. Since this culture values luxury and relaxation, McCoy's affinity for these also puts him at odds with Spock, a disciplined and rigid Vulcan. Bones's own Southern drawl is heard in This Side of Paradise (in which he makes a mint julep!) and The Deadly Years. This gentleman is also appealing to women, actually more of a lady-killer than either Kirk or Spock. McCoy is Jim's "guy" friend, ever ready with a stiff drink and a kind word.
On away missions and onboard ship, Spock and McCoy compete for Jim's affection. The Vulcan offers an eminently loyal, clear-headed companion (albeit with a dark side) while McCoy has the "human touch." Naturally Kirk values them both and wishes they'd just get along. He plays mediator and lightens up potentially hostile situations.
When the captain's not around, however, Spock and McCoy do get into heated disputes, usually after trying to help one another. McCoy objects to the first officer's command methods in The Galileo Seven and The Tholian Web, though in the latter case Kirk resolves their conflict from beyond the grave via record tape. Kirk faces the ultimate challenge in The Immunity Syndrome in deciding which officer and friend to send on a seemingly-fatal research mission. The captain picks Spock, perhaps because his Vulcan physiology gives him a better chance of survival.
Any differences are set aside when death threatens. In The Empath, the seriously-wounded McCoy admits Spock has "a good bedside manner." In All Our Yesterdays Spock carries the frozen doctor miles through the tundra. McCoy is equally supportive of the Vulcan in Amok Time and Spock's Brain, and will always give his reluctant patient medical care. Their friendship continues into in the film series: in The Search for Spock, McCoy discovers he is entrusted with Spock's katra or living spirit. He aids Kirk in finding Spock's body before undergoing an ancient and dangerous refusion technique.
In The Final Frontier, Kirk, Spock, and McCoy realize they are mistaken in assuming they don't have families: they have each other. The three don't separate for a moment in this story, whether confronting evil super beings or camping in Yosemite National Park. Their relationship remains dynamic - their views and personalities still conflicting - but their love of one another holds them together, whatever the universe throws at them. The Holy Trinity indeed.