While searching the house of the late Dr. Lanning the demolition bot outside

Gets reprogrammed to begin demolition immediately by the AI known as VIKI.

At one point the demolition bot is traveling through the house towards Detective Spooner as he runs away from it.

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Why didn't the demolition bot stop as per its 3 laws AI programming?

As I understand it VIKI was only able to override the 3 laws on the new NS-5 models, because of their wireless update capabilities. She wasn't able to override any AI device, otherwise she would have also done with the NS-4 models which were being replaced.

3 Answers 3


I doubt she could update all of the NS-4 models, as they'd all need to be put into update at the same time for the mass control effect she wanted. Plus they were probably limited in what sort of reprogramming they could undergo without becoming suspicious.

The Demo bot on the other hand probably has very simple software, and may not have even been 'sentient' like the NS-4/5 bots. Reprogramming a single bot that is constantly being given new demolition instructions is probably a lot easier, and risk free (considering the limited demolition time) than a world full of old heuristics robots for the foreseeable future.

  • I think that, as per Asimov's stories, all robots have the 3 laws, otherwise the public wouldn't accept their existence. Especially a robot as potentially dangerous as a demolition bot! Reprogramming doesn't include the 3 laws, otherwise criminals might be able to modify existing robots to commit crimes. This is all Asimov, of course; not sure about the movie.
    – Andres F.
    Aug 1, 2012 at 0:46
  • 1
    I'm not saying it didn't have the three laws, but some level of programming must be possible, even if it meant telling the demo pot that Spoonerism wasn't human, or overloading the method calls. Plus, there's having the three laws, and telling the public it has the three laws....
    – AncientSwordRage
    Aug 1, 2012 at 1:48
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    Having created the three laws... Asimov also took the opportunity to nullify them several times. In the Foundation & Robot books, you have them superseded by a higher law, but even in the earlier books you saw the simplest way to get past them; a robot not knowing what a human was or that a human was present. (See: The Naked Sun for Elijah Bailey explaining how it could be done. There are more examples in other works, such as the Bicentennial Man.) True, this story differs wildly from Asimov's... But even he liked to get past the three laws.
    – K-H-W
    Aug 1, 2012 at 4:19
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    One other easy method: The robot does not know what the consequences of it's actions will be. Telling a robot to bring a can of soda to someone will not cause a rule conflict... as long as the robot doesn't know that the soda is actually poisonous. It can require some trickery and awareness of the robot's limitations, but it can be done. The demobot didn't seem too bright; Vicki, understanding it's programming intimately, could have easily set it up to be fooled. Even more -- had it killed him and then learned of it, the conflict would have destroyed it's brain, and with it, the evidence.
    – K-H-W
    Aug 1, 2012 at 4:35
  • It's possible that she just told the bot "Hey, the guy who just went in left through the back door, where you couldn't see him. Oh, and the demo schedule has been updated." Aug 1, 2012 at 18:30

I do not think that the demolition robot was aware enough of its surroundings. It was not really a 'robot' it was just a machine.

All it knew was that it had to smash the house down. It would not have been designed with human detection equipment as it would have had a user (human or robot) which would perform that task, however when the user decides to not perform that task then it is not the demolition unit's fault any more than it would be a hammer's fault if I hit you with it.


It can also be argued that the Demo bot knew Spooner was there and carried on even though it knew but that this didn't break the 3 laws.

The Demo bot has received its orders from VIKI and VIKI is applying the 3 laws to the whole of humanity (i.e. the 1st law becomes "No robot may harm humanity" - although it can be argued that any action causes some harm to humanity so a better version of the law applied to humanity would be "Any robot must always act in the way that harms humanity the least"). When the laws are applied to humanity as a whole in this way then the death of a few humans becomes allowed (think of any group, fiction or not, that believes it works for "the greater good").

Asimov actually deals with applying the laws to humanity as a whole (although not human deaths). If you haven't already then I definitely recommend reading the original novel "I, Robot" by Asimov and also "The Rest of the Robots" by him as well :)

  • 1
    And also the rest of Asimov's writings? ;) Aug 5, 2014 at 3:45

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