(Note: If you haven’t read it yet, my introductory post on this Star Trek: The Original Series rewatch is a good place to start.)
Original air date: October 6, 1966
Crew death count: 0 (Yay!)
Bellybuttons: 1
I don’t dwell much on writing or production credits in these reviews, but I feel a comment on “The Enemy Within” writer Richard Matheson is appropriate. He wrote the novel I Am Legend, which gave us the disappointing film adaptation The Omega Man (1971) and the other disappointing film adaptation I Am Legend (2007) (I haven’t seen the first, and possibly best, I Am Legend adaptation, The Last Man on Earth (1964), with Vincent Price). He wrote the classic Twilight Zone episode “Nightmare at 20,000 Feet,” which featured William Shatner. In the 1970s, Matheson would write the novel Bid Time Return, adapted for the screen as the tragic romance Somewhere in Time (1978) with Christopher Reeve and Jane Seymour, and the screenplay for Steven Spielberg‘s first feature-length film Duel (1971), adapted from Matheson’s short story of the same name. I first learned of Matheson’s work during my teen years, during repeated attempts to watch late-night showings of The Incredible Shrinking Man (1957), adapted from his novel The Shrinking Man. I enjoyed the film, but the TV networks always aired it so late, I consistently fell asleep before the end. To this day, I have not seen the conclusion of The Incredible Shrinking Man. By 1966, Matheson was a widely respected science-fiction writer with considerable experience. This is the kind of talent Star Trek attracted early on.
In the case of “The Enemy Within,” the Enterprise is conducting a specimen-gathering mission on planet Alpha 177. A technician suffers a relatively minor injury and falls into some magnetic ore, which is carried with him when Kirk orders him back to the ship. This wreaks havoc with the transporter. Yet Scott soon beams up Kirk, despite having concerns about the transporter’s operation. When Kirk arrives in a weakened state, Scott escorts him to sickbay, and while the transporter room is unattended, another Kirk shows up. If his wild expression, dramatic lighting, and intense music weren’t enough clues, we quickly establish that the two Kirks are polar opposites. Each seems to know something abnormal has happened, but while Kirk #1 tries to soldier through, Kirk #2 is immediately antagonistic.

A small dog-like creature, presumably an Alpha 177 native, plays a bizarre but essential role. I can’t help but wonder how uncomfortable the real dog felt while forced to wear that ridiculous costume. The dog’s presence is never explained. Since animals are almost never seen on the Enterprise, I can only imagine they captured it for research purposes, which sounds terrifying and very unlike the Federation. Clearly, the dog is really here as a plot device, first to demonstrate what happened to Kirk, and finally as a guinea pig to test the repaired transporter. “The Enemy Within” is the first in a long series of Star Trek storylines about transporters run amok; just as we have surrendered our lives to algorithms that no one fully understands, inhabitants of the Star Trek universe seem resigned to this widespread technology that repeatedly turns on them.
Once on the ship, Kirk #2 immediately pulls a Harvey Weinstein, wandering the ship’s corridors with a carafe of Saurian brandy and heading straight to Yeoman Rand’s quarters. Poor Yeoman Rand. Kirk #2 tells her she’s “too beautiful to ignore…too much woman,” and then tries to rape her. I don’t know how this played in 1966, and I know my younger self didn’t appreciate the scene’s significance, but it is justifiably upsetting to watch today. Thankfully, Rand fends off Kirk #2, and calls for help from a passing crew member when the door to her room opens (thanks heavens for those automatic doors). More on the witness shortly. A piece of abstract art is displayed in Rand’s quarters, positioned on an easel that implies this could be Rand’s own work. It’s a subtle piece of character development that makes me wish Rand had been given a more substantial role in the series.

Clearly, Matheson took a lot of inspiration from Robert Louis Stevenson’s 1886 novella Strange Case of Dr. Jekyll and Mr. Hyde. In Stevenson’s story, Henry Jekyll, born into wealth and good health, finds himself living a dual life, a public, respectable man of science and a private, self-indulgent jerk. Jekyll devises the means to literally switch between these personalities, allowing his dark side free reign under a separate identity without burdening his better self with guilt or consequences. He learns the hard way that life is not so simple. Choice is one of the main divergences between Jekyll and Hyde and “The Enemy Within”: Jekyll went in search of a cover story, whereas Kirk has duality forced upon him. The nature of Kirk’s divide, and how to resolve it, is the primary conflict of “The Enemy Within.” Good and evil are the terms commonly used in the dialogue. There are a few other ways to view the split, all hinted at in the episode:
Intellect vs. ignorance: Kirk #1 is able to reason through situations, or, as his ability declines, allow others to help him reason through them. Kirk #2 acts without thinking, and has to go to increasing lengths to cover his tracks, which he does poorly. Kirk #1 can understand the necessity of uniting with his darker self. Kirk #2 literally screams, “I’m Captain Kirk!” and clings to a selfish path, unable to comprehend he’s on the road to self-destruction. Watch as Kirk #2 knocks the books off the shelf in his quarters, rejecting a life of the mind. If asked, Kirk #2 probably couldn’t even explain why he wants to be captain (much as Charlie X probably couldn’t have explained why he so desperately wanted people to like him). He just wants it.

Human vs. animal: Kirk #1 refers to Kirk #2 as “a thoughtless, brutal animal.” This relies on the historic notion that humans are superior to animals simply because we can make speeches and build sports cars. Judging by how much public discourse is in the gutter, and how eagerly we create the tools of our own destruction, one has to wonder if the animals possess the real intelligence. However, this division might hold up better in the 23rd century, where humans are operating at a higher level than today.
Logic vs. emotion: McCoy tells Kirk #1 he has the logic Kirk #2 lacks. Despite using the terms good and evil, this is the interpretation that Spock seems truly drawn to. More on Spock’s reaction, so critical to this episode, later.
Female vs. male: Women are thoughtful but weak, like Kirk #1, and men are decisive and powerful, like Kirk #2. An offensive concept based on gender stereotypes, but considering the state of affairs in 1966, I have no doubt that it was implied. Note that the rational world of the Federation prefers Kirk #1, while stubbornly clinging to brutality as a necessity of leadership. This theme will be carried to a bizarre extreme in the season three episode “Turnabout Intruder.”
Courage vs. fear: McCoy makes a comment to this effect, that intelligence and logic are the source of “man’s essential courage,” and it is this dichotomy that saves Kirk in the end. The dog doesn’t survive being reunited with its angry self in the repaired transporter. Spock concludes this is because the dog is unable to manage its fear. Kirk #2 is terrified, but Kirk #1, as the one with courage, can survive what the dog couldn’t. It’s important that Kirk #1, the more passive version, is the courageous one, because Kirk #2 is a classic bully, bluster without substance.
Public vs. private: Even before social media, it has always been human nature to present a more civilized face to the public compared to our private lives. Jekyll and Hyde was partly a comment on Victorian England, where the cultured classes devoted considerable attention to public perception while conducting less savory conduct behind closed doors. Robert Louis Stevenson attended the trial of a friend who had been accused of murder. It was discovered that the friend had apparently taken several lives. Jekyll and Hyde was partly Stevenson’s attempt to resolve the paradox of a murderer hiding before his very eyes as a man of good public standing. In “The Enemy Within,” Spock and Kirk #1 both comment on the importance of the captain maintaining a proper image with the crew.
None of these binary constructs holds up perfectly, because the two Kirks are exaggerations for the purpose of telling a story. Clearly, the binary argument is too simplistic. Human consciousness is too complex for a 0 or 1 reduction.

My earlier Weinstein reference is deliberate. Despite Kirk #2’s shocking behavior, the crew is slow to confront the captain, at least as slow as a one-hour TV episode allows. He practically assaults McCoy for the Saurian brandy, which leads to nothing more than a gentle inquiry from Spock, with no follow-up from McCoy. Kirk #2 knocks unconscious the crew member who witnessed the assault of Rand; when that witness steps forward, McCoy hushes him and sends him back to his sickbay bed. In our 21st century world, we find sexual predators protected by subordinates who are afraid of losing their jobs or having their careers sabotaged. “You know who I am,” is how Kirk #2 challenges his bridge staff late in the episode. This protection sometimes comes from victims, and we see this with Yeoman Rand, who apologizes for accusing Kirk, saying, “I don’t want to get you into trouble.” She goes so far as to say, “I wouldn’t have even mentioned it,” if not for the additional witness (a courageous crew member who doesn’t hesitate to speak up). When Kirk #2 approaches Rand late in the episode and makes a half-hearted apology, with a suspicious suggestion to come to her quarters later, she agrees. What choice does she have? In the final scene, she even seems about to apologize again, to integrated Kirk, knowing that a rapist is part of his personality. This burden of constantly being expected to apologize for the crimes of others was one of the driving forces behind the #MeToo movement.
Predators are also protected by friends who will later claim they couldn’t believe the person they knew was capable of such behavior. How much does this apply to “The Enemy Within?” Spock, having seen the duplicated dog in the transporter room, quickly concludes that there are two Kirks on the Enterprise. This only works with Spock because we know that, despite his friendship with Kirk, he is the one person on the ship capable of putting emotions aside and confronting the truth. Anyone else on the Enterprise should be suspect if they tried to defend Kirk in a similar manner. Which makes it all the more disturbing when Spock, at the end, asks Rand, “The imposter had some interesting qualities, didn’t he, Yeoman?” Spock’s emotional detachment certainly can’t include tolerance of sexual assault.

Just as Jekyll and Hyde couldn’t exist indefinitely in their divided state, so the two Kirks appear to suffer from a progressive condition that affects each differently. Kirk #1 loses his mental faculties while Kirk #2 goes into physical decline. As soon as the dog is beamed up as opposing twins, Kirk #1 seems to realize what has happened, then immediately forgets, until Spock announces the presence of an imposter. Later, Kirk #1 says decisions are becoming “more and more difficult.” Kirk #2, already lacking Kirk #1’s intelligence, suffers physically, driven forward only by an anger that exists solely for its own sake.
Shatner’s acting carries the episode in his ability to distinguish the two Kirks. But Spock’s handling of the situation is also essential to our story. Exploration is job one for the Enterprise, and Spock does exactly this, saying, “We have here an unusual opportunity to appraise the human mind. Or to examine, in earth terms, the roles of good and evil in a man.” Only Kirk’s declining health prevents further study. It’s not just Spock’s intelligence that helps him interpret the situation; he spells out what was already suggested in “The Naked Time” (which makes an intriguing double-feature with “The Enemy Within”). He understands Kirk’s situation because his own human and Vulcan ancestry are in constant conflict with each other. This is why he believes Kirk can survive the unification that killed the dog, because Spock nurtures his own logic to win out over darker emotions. Yet it’s Spock’s human tendencies that give him the presence of mind to apologize to Kirk for appearing insensitive. “It’s the way I am,” he says.

So even Spock implies that a little coldness, or darkness, is necessary to a complete life. By now, we’ve repeatedly seen Spock’s rapid calculations in determining the lesser of two evils. Presumably this same quality allows Kirk to make life-or-death decisions. But just how much coldness are we willing to accept as natural? McCoy’s final comments, the message that we are presumably meant to take from the episode, is that this darker side is “human.” Spock and McCoy both conclude that this is part of Kirk’s exceptionalism, the quality that makes him a leader. If they’re right, that this darkness is an evolutionary holdover humanity can’t live without, that is bad news for us. Are we really prepared to accept the tired old excuse that boys will be boys? Is Yeoman Rand really supposed to keep reporting to Kirk, knowing that deep down inside he harbors a potential rapist? When Kirk #2 (let’s say it again, he’s the sexual predator) cries, “I want to live,” Kirk #1 shouldn’t have to promise, “You will.” I can confess to ogling a fair number of women over the years, and that’s problematic enough. But I never entertained a desire to commit assault, and I’m not a CEO, military officer, or politician. I don’t accept that only predators like Weinstein, or calculating narcissists like Bezos and McConnell, can lead us, because that would certainly make humanity a lost cause. I suspect even Richard Matheson didn’t fully accept this “evil is necessary” line of thinking. It’s no accident that the crew repeatedly refers to Kirk #2 as an imposter. Spock even refers to Kirk #2 as “it” at one point.
Two Bruce Lee statements came to mind while I watched “The Enemy Within.” The first is, “Emotion can be the enemy, if you give in to your emotion, you lose yourself.” Lee didn’t mean that we shouldn’t experience emotions, that would be impossible. He presumably meant that we shouldn’t let transient emotions guide our decision-making. Kirk #2 isn’t just thoughtless, but aggressive in his cruelty. Hyde suffered from equally negative emotions, targeting only those he could easily overpower, a young girl and an old man. Kirk #2 attempts the same when he assaults Rand. Kirk #1 has the ability to reason beyond short-term emotions and has to take charge of their combined fate. While each needs the other, Kirk #1 is clearly more oriented toward long-term survival.
Lee also said, “Be like water making its way through cracks. Do not be assertive, but adjust to the object, and you shall find a way around or through it. If nothing within you stays rigid, outward things will disclose themselves.” Kirk #1 remains adaptable while Kirk #2’s rigidity will be their undoing. Perhaps this offers a more contemporary interpretation of the Kirk divide. Kirk #1 represents humanity’s better nature, open-minded and ready to change with new information and changing circumstances. Kirk #2 represents willful ignorance that will kill them both. Imagine an entire society as inflexible and self-indulgent as Kirk #2, perpetuating systemic racism, climate change denial, and outrageous conspiracy theories.

This interpretation still isn’t a perfect fit because it doesn’t account for Kirk #1’s dependence on Kirk #2. Again, either/or reductionism is insufficient. Life isn’t a zero-sum game. We have to allow for multiple paths forward, and “The Enemy Within” acknowledges this at the end. Spock and McCoy feud over what action to take. Spock urges Kirk to go through the transporter right away, because a landing party, led by Sulu, is freezing on the planet’s surface and needs to return to the ship. McCoy pleads for a full autopsy on the deceased dog, because if Kirk dies in the transporter, the landing party will die anyway. It’s Kirk #1 who understands they are both correct. He will go through the transporter, but instructs McCoy to conduct the autopsy in case a Plan B becomes necessary.

One of Star Trek’s greatest strengths has always been to demonstrate that the most difficult journey is within ourselves. Sometimes confronting our own shortcomings is the only way forward. As Q reminds us in the TNG series finale “All Good Things…,” the real exploration is “not mapping stars or studying nebulae, but charting the unknown possibilities of existence.” “Evil” Kirk in “The Enemy Within” may be a caricature, but he underscores the necessity of self-awareness. Exploration involves great risk. One of those risks is that in venturing forth to understand others, we may be forced to reckon with our own history. It will be uncomfortable, painful at times, but in doing so we may make unknown possibilities known, and thereby achieve wonders.
Next: Mudd’s Women