Comparisons
Spock was the first of a now-familiar type in Star Trek, the outsider struggling with the concept of humanity. Whether rejecting it, striving to find it within themselves, or simply being wry observers, these characters often prove the most interesting and dynamic of their respective crews. What does Spock have in common with his successors? How do they differ? We'll see.
Data. (Brent Spiner, Star Trek: The Next Generation) In the early days of TNG, Data was widely viewed as a Spock substitute. True that both are science officers who convey logical conjunctures in an even tone, compute and analyze, pursue art practices, care for pets, are physically formidable, and most of all, are unemotional. But what Spock represses within himself, Data seeks without. The Vulcan finds possessing a human half difficult, but the android struggles equally in having a human form without feelings. The two actually meet in TNG's Unification, when the curious Data can at last question the legendary figure on his life choices.
In Generations, Data retrieves his long-lost emotions chip, and must learn when it's appropriate to display one's feelings, and how. Spock makes similar decisions in The Undiscovered Country.
More parallels appear as the films progress: in First Contact, Picard risks all he has for his friend (as Kirk does) and in Nemesis, Data sacrifices himself to get the Enterprise out of danger . . . after downloading his memories to his prototype B4. All this recalls the final, spiraling events of The Wrath of Khan.
Data begins as a more innocent, naïve character than Spock, but strives to evolve. In his desire to become fully human he's the Vulcan's opposite, yet both must ultimately accept what they are to find peace.
Worf. (Michael Dorn, Star Trek: The Next Generation and Deep Space Nine) Like Spock, the Klingon is the first of his race to be trained by and serve in Starfleet. His past is also similar, raised among a people (here humans) who didn't understand his natural instincts. He too finds a home in the Federation, and signifies the Klingon Empire's increasing cooperation. Much of human behavior still mystifies him, and his shipmates are equally taken aback by some Klingon customs. Worf provides a bridge between cultures, and is as much a diplomat as a warrior. Still, he wishes to retain his martial ethics, quite the reverse of Spock's beliefs in peace. The Vulcan would not approve of Worf's inclinations to anger or sullenness either, but he would understand the sources of such volatile emotions.
Deanna Troi. (Marina Sirtis, Star Trek: The Next Generation) The Enterprise-D's half-human, half-Betazoid councilor also knows what it's like to be torn between two worlds. Yet her dilemmas come more in the form of family pressure than philosophical conflict, and can mainly be traced to her overbearing, telepathic mother. While Vulcans are touch telepaths, Betazoids can fully communicate via thought. Their abilities also allow Troi to sense others' emotions, and her training allows her to assess them. Troi's job encourages the development of the emotions that science officer Spock shuns, making the two characters quite different.
Tuvok. (Tim Russ, Star Trek: Voyager) He is the first Vulcan regular since Spock, and a full Vulcan too. As such he is more at ease with himself than his predecessor, though his suppressed emotions are even more intense. While Spock has his dark side, he also must hide his feelings of affection for friends and family. While Tuvok finds outlets for his "positive" emotions - creating a strong marriage, raising two children, maintaining a friendship with Captain Janeway - he struggles to keep his violent impulses in check. He finds some release in his duties as security officer and in martial arts training. In many ways Tuvok begins his epic voyage as an older, wiser officer than Spock, but still has to confront the basic conflicts of the Vulcan psyche.
The Doctor. (Robert Picardo, Star Trek: Voyager) The Emergency Medical Hologram begins as something Vulcans would have first been to humans: an entirely different form of life. But while Vulcans are humanoid, the Doctor is photonic, which has it's advantages as well as complications. The EMH can pass through solid matter, change his form (tricks to rival Spock's various mystical techniques), tap into vast amounts of computer data, and does not age. But like Spock with his long life span, the Doctor must watch his human friends grow old and his world change. He also must stand up for basic rights not afforded to him since he isn't an organic being. (Spock faced discrimination too.)
The Doctor isn't content to stay within the limits of his programming and takes every opportunity to expand his range of knowledge and experience. Spock makes an effort to be a well-rounded individual, but lacks the ambition to command a ship or otherwise be in the spotlight. The Doctor has no such qualms, becoming an opera star and adding command subroutines to his program (both with unexpected results.) One might suspect that - like Data - what the EMH wishes most is to be human. Yet in the sixth season the Doctor admits he enjoys his unique nature. He's proof that, as Spock always maintained, one can develop as a person without becoming a human.
Seven of Nine. (Jeri Ryan, Star Trek: Voyager) Freed from the Borg collective by Captain Janeway, Seven comes to see her humanity as a birthright to be reclaimed. Since she was assimilated as a small child, adapting to life among humans is difficult. As important to her as Spock's logic is Borg efficiency. She often tries to make the ship run more smoothly, even if it means friction with the crew. Unlike Spock, who has always had impeccable manners, Seven is at first critical, confrontational, brash, and dismissive. Janeway and the Doctor, however, are able to instruct her in the social graces, and Seven goes from a lost and angry child to considerate young woman. Her cortical node doesn't allow her to express a great range of emotion until it is removed in the seventh season, so until then she possesses a Vulcan-like cool. Though she does utter "logic is irrelevant" to Tuvok, she does appreciate Vulcans. Seven is also the most dynamic character on Trek after Spock, changing greatly over four years. She too comes to realize that "human flaw", which she tried to eliminate as a Borg drone, has value.
T'Pol. (Jolene Blalock, Enterprise) Many casual TV viewers would only know that T'Pol is the same race as Spock due to the ears, it must be said. Smug, disdainful, and condescending, T'Pol hardly seems to hail from a race that values peace and diversity. While Spock realized many of his abilities were superior to those of humans, he never considered himself to actually be superior. This attitude, however, seems a given among the race in T'Pol's time, and many don't believe she'll last on a mission with humans. Her presence on an Earth ship undercuts the importance of Spock's decision to join Starfleet a century later, and many details of her character and people contradict what has long been understood about them. (She says not to like the smell of humans, whereas Vulcans are not supposed to have a strong olfactory sense, for example.) It's hard to accept T'Pol as Spock's kin, or see her "struggle" as unique or compelling. We can hope The Powers That Be are soon able to once again create characters that truly explore what it means to live as or live with humans.