No matter which side of the great Tuvix debate you fall on, this season 2 episode of Star Trek: Voyager is a powerful, thought-provoking story.
Greater Than The Sum
When being transported from the surface of a planet, Tuvok and Neelix are accidentally merged into a single being, Tuvix. Tuvok, a bastion of Vulcan logic and reason, and Neelix, a warm-hearted and emotional Talaxian, stand in sharp contrast to each other.
When The Doctor determines that Tuvix is indeed healthy, and there is no known way to reverse the process, Tuvix begins integrating himself with the crew as a blend of both men. As he settles in, other members of the crew explicitly observe that he seems to be more than the sum of his parts, better than either Neelix or Tuvok. This addresses the classic debate about a system being greater than the sum of its parts and if so, the reason behind this behavior. Tuvix seems to be able to draw on Tuvok's logic and Neelix's intuition and combine these strengths together in ways that neither of them could on their own.
While it takes everyone, especially Kes, some time to adjust to Tuvix, he is patient, kind, and insightful and eventually they come to really value him. Just as Kes tells him that she is interested in becoming friends and eventually more than friends, the spell is broken as The Doctor finds a way to separate the two original crew members from Tuvix.
A Metaphor For Voyager Itself
Let's step back a minute and examine the intimate conversation between Kes and Janeway in her quarters. Janeway reveals that she misses Mark, her fiancé, and struggles with the idea of one day letting go of him (because Voyager is so far from home). This parallels the struggle with letting go of Tuvok and Neelix, who are similarly lost and inaccessible. This scene is really valuable as a metaphor for Voyager's predicament: lost in the Delta Quadrant with no way back to their family and friends. Moreover, Janeway is normally portrayed as a strong, confident leader and you do not often get such an honest insight into her emotions and vulnerabilities.
Janeway's Moral Dilemma
The most powerful part of this episode is Janeway's debate about what to do - allow Tuvix to remain or to restore Neelix and Tuvok, thus condemning Tuvix to cease to exist. On the one hand, Tuvix vehemently does not want to die, and resists suggestions that he should proceed with the procedure. On the other hand, it is Janeway's responsibility to advocate for those whose voices cannot be heard.
Ultimately, she decides to separate Tuvix and restore Tuvok and Neelix. He aggressively resists the procedure, pleading with each member of the bridge crew to help him. In an emotional, riveting scene, The Doctor refuses to perform the procedure, citing the Hippocratic Oath, and forces Janeway herself to beam Tuvix out of existence. After Tuvok and Neelix are restored, they do not say a word, and Janeway's face as she walks out of sickbay conveys the incredible weight of her choice and actions:
