The Enterprise beams down to the planet Scalos in response to a distress call, only to find no evidence of life at all. When one of the disposables suddenly disappears, the ship experiences bizarre malfunctions orchestrated by some mysterious ‘enemy’. Kirk doesn’t know what to do, so he just lets the situation play out. While drinking coffee on the bridge, the world around the captain seems to slow down, and then a mysterious woman appears, calling herself Deela. She says she has accelerated him to a superfast speed where even a phaser blast won’t hurt her. Evidently, Kirk, and the missing redshirt, were sped up by a race of aliens who live their lives at a faster rate. The aliens need to use the Enterprise and crew to reproduce their species, which is in this state by the same disaster that made them super-accelerated. However, when humans are brought up to the super-accelerated speed, they die because their bodies burn out. Spock discovers that the coffee Kirk was drinking, as well as the Scalosian water, is contaminated with a substance that caused the acceleration.
As Kirk is fighting to save his crew, and the Scalosians are fighting to save their species, they are locked in a zero sum-conflict. The situation reminds one of a trolley problem, but a one to one variation of the original version. There is only a small group of Scalosians left trying to repopulate the species, and there is only a finite number of Starfleet crew-members onboard the Enterprise, human or otherwise. However, the Scalosians represent the last of their kind, and thereby the elimination of an entire species, whereas more humans exist outside the Enterprise. The loss of the Enterprise crew would not make a dent at all in the galaxy’s human population, but the loss of this group of Scalosians would be equal to the loss of an entire species from the universe. Does that make the Scalosian lives worth more than the human/Starfleet lives? Without considering the implications of the species, it is a simple one to one value. To use the trolley metaphor, there is one person on one track and another person on the opposite track, the value of their lives is equal, so which one do you sacrifice?
More accurately, there is a human on one track and an alien on the other, so in this situation we are naturally more drawn to the human, because we identify with the human. However, we also tend to be quite biased toward endangered species, giving them more value and protection because of their rarity and fragility. At the individual level, considering all life equal (a very Starfleet viewpoint), there is simply one life on one track and another life on the other track, with no way to really make a value judgment one way or the other. However, when we weigh the difference between the individual lives, the human friends we have grown to love over the course of three Star Trek seasons verses these new invasive, and possibly selfish or evil aliens, it seems we must side with the humans. However, on a species level, the last of an endangered species versus a comparably small sample of the human race, which would not be endangered by their loss, the endangered species would have more value.
Who do you sacrifice? Breaking down the issue above, it seems that considering all life to be equal was not helpful in answering the question, because we just end up with an equal one to one ratio, with the survival of either side not being inherently more or less valuable. In the second instance, valuing human life just because we are human does not seem like an objective value judgment. Would it represent an overall moral choice if a Scalosian decided that the Scalosians have more a right to live? One could argue that the Scalosians were predatory, because they sought out a victim to use and sacrifice for their reproductive strategy, but the Enterprise found them first. This leads down an endless rabbit hole of species exploiting other species for their own survival and reproduction.
The trolley problem has challenged philosophers for decades, but no one is literally flipping switches on a train track to save the lives of five people (or one?). However, issues in environmental ethics and biodiversity are far more pertinent. Strategies aimed at saving endangered species will certainly impact humans, but should it cost human life? What if the species is parasitic? In the case of the Scalosians, Kirk and crew abandoned their mission to ‘seek out life’ and instead, chose to eliminate the parasites. Spock deduced that the acceleration was caused by contaminated water, and he teams up with Kirk to overthrow the invading aliens and destroy their equipment. Despite the philosophical dilemma, survival of the fittest applies even in the microcosm of a spaceship. In an effort to preserve our definition of biodiversity, choices are made about which species will live or die. Only we can flip the switch.