In Larry Niven's The Ringworld Engineers, Louis Wu, Chmeee, and Harkabeeparolyn

travel to the Ringworld's control center on the Map of Mars in the Ringworld's great ocean, in order to find some way of re-centering the giant structure on its Sun.

But there they run into Teela Brown, who

remained behind from Louis and Chmeee's last visit to the Ringworld. She's eaten Tree-of -Life root and become a "protector".

But it's weird:

Protector-Teela tells them that there is a way to save the Ringworld, but doesn't tell them what it is. She's actually come there to try and stop them.

Teela tells Louis:

"Furthermore, there is a solution that does less damage, yet it is too much damage, and I cannot permit it."

Teela's solution will kill 5% of the Ringworld's population to save the other 95%. That's 1,5 trillion sapient humanoids out of 30 trillion. It will be a slow death by radiation.

Although Teela

Knows it has to happen, and drops hints to give Louis a chance to figure it out, she nevertheless makes them fight and kill her in order to gain access to the control room.

Louis and Chmeee's advantage is, as Louis puts it, is that

Teela is fighting to lose. One of the many strange compulsions of Protectors forces her to engage in "doublethink" to avert disaster.

Why can't Teela resort to simple utilitarianism?

  • 3
    ...Because she's not a utilitarian? Aug 18, 2019 at 1:50
  • 1
    @ApproachingDarknessFish Except that she clearly is, only in a twisted and self-defeating way.
    – Spencer
    Aug 18, 2019 at 1:53
  • 2
    It's an IMO flaw in Niven's writing where he imagines beings with an extreme form of genetic predestination. Cowardly Puppeteers, suicidal Kzin, programmed Protectors -- in the extreme form, none of these are likely to be favorable traits in an intelligent being and would not have evolved.
    – Mark Olson
    Aug 18, 2019 at 8:40
  • 1
    @MarkOlson "Louis, no sapient being interrupts a defense mechanism". -The Hindmost. There's some stuff in Ringworld and RE that explains the evolution of puppeteer behavior in a more nuanced way.
    – Spencer
    Aug 18, 2019 at 15:14
  • 2
    I'm not sure all the spoiler markup is really necessary. If I wanted to avoid spoilers for ringworld-engineers, I wouldn't read the question. Aug 19, 2019 at 12:27

1 Answer 1


Protectors are psychologically "hardwired" to protect all their offspring at all costs. They make this decision by smell (pheromones). The other inhabitants of the Ringworld would count for Teela's human personality, but not for the protector instincts.

Teela lived with Seeker for two decades in the 5% part of the Ringworld that had to be torched and had a child with him (cf Ringworld's Children). So she could not bring herself to "pull the trigger" even if she made the rational decision that she should.

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