<P> One interesting aspect of HAL's plight, noted by Roger Ebert, is that this supposedly perfect computer actually behaves in the most human fashion of all of the characters . He has reached human intelligence levels, and seems to have developed human traits of paranoia, jealousy and other emotions . By contrast, the human characters act like machines, coolly performing their tasks in a mechanical fashion, whether they are mundane tasks of operating their craft or even under extreme duress as Dave must be following HAL's murder of Frank . For instance, Frank Poole watches a birthday transmission from his parents with what appears to be complete apathy . </P> <P> Although the film leaves it mysterious, early script drafts made clear that HAL's breakdown is triggered by authorities on Earth who order him to withhold information from the astronauts about the purpose of the mission (this is also explained in the film's sequel 2010). Frederick Ordway, Kubrick's science advisor and technical consultant, stated that in an earlier script Poole tells HAL there is "...something about this mission that we weren't told . Something the rest of the crew knows and that you know . We would like to know whether this is true", to which HAL responds: "I'm sorry, Frank, but I don't think I can answer that question without knowing everything that all of you know ." HAL then falsely predicts a failure of the hardware maintaining radio contact with Earth (the source of HAL's difficult orders) during the broadcast of Frank Poole's birthday greetings from his parents . </P> <P> The final script removed this explanation, but it is hinted at when HAL asks David Bowman if Bowman is bothered by the "oddities" and "tight security" surrounding the mission . After Bowman concludes that HAL is dutifully drawing up the "crew psychology report", the computer makes his false prediction of hardware failure . Another hint occurs at the moment of HAL's deactivation when a video reveals the purpose of the mission . </P> <P> Stanley Kubrick originally intended, when the film does its famous match - cut from prehistoric bone - weapon to orbiting satellite, that the latter and the three additional satellites seen be established as orbiting nuclear weapons by a voice - over narrator talking about nuclear stalemate . Further, Kubrick intended that the Star Child would detonate the weapons at the end of the film . Over time, Kubrick decided that this would create too many associations with his previous film Dr. Strangelove and he decided not to make it so obvious that they were "war machines". Kubrick was also confronted with the fact that, during the production of the film, the US and USSR had agreed not to put any nuclear weapons into outer space by signing the Outer Space Treaty . </P>

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