Let me back up a bit, so that you know what I am going on about. I think Wikipedia can probably sum-up better than I can:
Some aspects of the story [of The Terminator] were sufficiently similar to two episodes of the TV series The Outer Limits — both episodes written by Harlan Ellison — that Ellison pursued legal action against Cameron. Cameron settled out of court and acknowledged Ellison's work in the film's credits. However, some time later, the credits were mysteriously taken out (rumored to have been removed by Cameron himself). Another lawsuit was filed until the credit was reinserted.
The episodes in question were called "Soldier" (which involves a specially-trained man accidentally sent back in time) and "Demon with a Glass Hand" (concerning a time traveler who suffers memory loss and relies on a computer chip implanted in his artificial hand to give him information about his mission while assassins sent from the future attempt to kill him). There is also some similarity between the concept of Skynet and the evil intelligence featured in Ellison's short story, "I Have No Mouth, and I Must Scream".
Yes, all three of these stories have some story elements in common with The Terminator. In fact, some of the similarities are quite striking. But how does that give Ellison the right to claim them as his own? Authors have been taking story elements from prior sources for centuries. Hell, I don't think Shakespeare wrote a single original story (an extreme example, perhaps).
Even if Cameron really did piece his film together from the elements in these three stories, I would have thought there was enough difference to nullify any claim of plagiarism. Cameron has maintained that his story is completely original, and not at all taken from Ellison's work. Still, as I say, if Cameron was borrowing from Ellison's work, what is wrong with that? Stories are meant to take inspirations from other stories.
If in The Terminator almost the same series of events happened as in one of these stories, then I think then and only then would Cameron have a case to answer. But that's simply not the case. Instead we have a few similarities here and there in what is essentially a completely different story.
But, here's what I would like to know - does Harlan Ellison acknowledge that his own stories are rip-offs of HG Wells? If The Time Machine was not in the public domain, would Ellison be happily paying royalties? And, on the flipside, why has Ellison not sued the creators of the film WarGames, which also shares a story element with the above short story?
There are very few original story elements out there - what matters is the final product, the complete crafted story. Even if that story is a pastiche of older elements, it is still crafting something new. Sure, there are some scenarios when an author has a legitimate case to answer for, but the proof is in the watching. After watching both these episodes, and reading the short story, I feel as though I have experienced four distinct stories (six when you add the other two Terminator films). I enjoyed all of them (although Terminator 3 much less so), and feel like there was very little doubling up. So, why does Harlan Ellison think he has the right to extort money from anyone who writes a story that is simply similar to his own? All writers of science fiction be on notice - Ellison is coming after you, because he owns your ideas.