The biggest theme that runs throughout the Terminator series is that of humanity over machinery. Humans face extinction because they've become obsolete in a world dominated by technology. In a 2015 article on technophobia published by The Atlantic, Christopher Bader, a professor of sociology at Chapman, said, "People tend to express the highest level of fear for things they're dependent on, but that they don't have any control over, and that's almost a perfect definition of technology."
Skynet is the franchise's representation of this fear. With the exception of Salvation, which takes place post-Judgement Day, the driving force behind Terminator's characters is to prevent Skynet from coming online, an act that leads to its declaration of war against humans. In Salvation, the hope is to overthrow Skynet and return the world to humans. Skynet is seen as unfeeling, uncaring, and ruthless. Humans, at their best, are the exact opposite. It's the hope that humanity can face its fear of technology and fix its mistakes that runs through all of the films.
