In the Voyager episode Tuvix, a transporter accident combines Neelix and Tuvok, two of Voyager’s crew, into a single person named Tuvix. Tuvix had memories of both characters and a personality that combined traits from both of them. He lived on the ship for some time before a possible cure was discovered. Unfortunately, the cure meant killing Tuvix to restore Neelix and Tuvok. Tuvix himself did not want to die and begged to be allowed to live. The doctor refused to perform the separation, and it was up to Captain Janeway to perform the operation which would kill Tuvix but give her back her two former crewmates.
The Mishnah records that we do not kill one person to save another. The Talmud also derives that although one may violate almost any law in the Torah to save one’s life, murder is one of the few commandments that may not be violated to save a life. In a famous comment, the Talmud rhetorically asks “Do you think your blood redder than his?” This is brought down in the Shulchan Aruch and Rambam (among other halachic works) as one of the so-called ‘big three’, joining idol worship and illicit sexual relations as the three laws that cannot be violated to save one’s life. In other words, you cannot kill Tuvix to save Tuvok.
When faced with such a dilemma, some are tempted to do simple math and say that saving two lives is more important than one. However, halacha does not see it that way – every life is of infinite value. Just as Neelix and Tuvok’s lives are of infinite value, so is Tuvix’s. Halacha also generally prefers inaction which leads to someone’s death to action which leads to death, as an action that leads to death is murder. Rambam provides a case where a group of people are told to hand over a single member of their group to be killed or else they will all be killed. In such a case, they should all allow themselves to be killed rather than to take an action that is tantamount to murder. Halachically, Janeway was not allowed to murder Tuvix, even to save two other people. We see a reflection of this in the Doctor’s actions in this episode. While he worked valiantly to try and save Tuvok and Neelix, when it came time to actually perform the procedure he couldn’t do it because it meant killing Tuvix – something he refused to do.
There are some exceptions to the general rule, but none of them really apply here. One of the exceptions is based on the story of Sheva Ben Bichri in II Shmuel. The townspeople turn over Sheva Ben Bichri to Yoav’s army to prevent their entire city from being destroyed. There is a debate in the Jerusalem Talmud over whether this action was appropriate or not. One opinion is that the townspeople were allowed to hand over Sheva Ben Bichri because he was specifically singled out by Yoav’s army. The other opinion is that the townspeople were allowed to hand him over because he was guilty of a capital crime, and therefore was liable to be put to death anyway. There are rishonim on both sides of the issue, and Rema records both opinions in the Shulchan Aruch. Tuvix clearly committed no crime, so he clearly could not have been handed over for death according to the second opinion. This exception is also somewhat inapplicable to our situation because there is no external force that is threatening to kill Tuvok and Neelix (or anyone else) if an individual is not sacrificed.
The second exception is if someone volunteers to be sacrificed for the greater good. Rabbi Eliezer Waldenburg, a 20th century expert on medical ethics discusses the topic of someone putting themself in danger in order to save another. While he concludes that someone is not obligated to sacrifice themself to save others, it is permissable. For example, spock’s act of self sacrifice in Star Trek II was permissable. if Tuvix had volunteered for the operation in order to save Tuvok and Neelix he would have been allowed to. However, it is clear from the episode that he doesn’t. In his final scene on the bridge he begs the other members of the crew to be allowed to life as he clearly does not want to die.
We can see that halacha doesn’t allow murder, even in order to save the lives of multiple other people. The general principle that inaction that leads to something negative is preferred to taking an action that leads to something negative is brought up often when discussing cases like these. Unless Tuvix had volunteered to sacrifice himself to save Tuvok and Neelix, Janeway did not have halachic grounds to kill him, even to save two other members of her crew.