The Terminator - The Perfect Time Travel Paradox

Before I get into this, I will state that I love The Terminator movie franchise. It is my all time favorite Sci-Fi movie series and I am not trying to plot-hole pick, damage or put any of the movies down or ruin any of the movies reputations in any way by analyzing the paradox that the original The Terminator movie contains.

However, it's a movie about Time Travel, and all Time Travel movies create paradoxes within them, so let's discuss what I consider to be the most perfect Time Travel paradox contained within a movie.

SPOILER ALERT !! - This post will discuss all aspects of The Terminator movie and hence if you haven't watched the movie, stop reading and go watch it now!

Time travel paradoxes fascinate us because they attack something extremely fundamental: our built-in model of how reality works. Our Brains Are Built Around Forward Causality.

Human cognition is structured around:

• Cause → Effect
• Past → Present → Future
• Memory of past, ignorance of future

This isn’t just cultural — it’s biological. The thermodynamic arrow of time (entropy increasing) gives us irreversible processes: glasses shatter, people age, eggs scramble. So if you imagine: smashed glass existing before the glass was dropped, it violates the way our brains are wired to process reality. We don’t just think linearly — we experience linearly.

A time-travel paradox creates a logical loop where:

• Event A causes Event B
• Event B prevents Event A

That’s a contradiction. And contradictions are cognitively uncomfortable. Our brains crave coherence. When we encounter logical impossibility, it creates a kind of mental “itch” we want to resolve.

Example:

• I am very very thirsty so I drink several glasses of water and feel refreshed and hydrated.
• I then travel back in time 24 hours and smash the glass that I drank the water from.
• I return to my own time. How can I feel refreshed and hydrated if the glass that I drank from no longer existed when I drank from it.

By changing the past, I have changed my future. Future me went back in time and smashed the glass. Past me still got thirsty and used a different drinking vessel because the glass wasn't available. Future me now has no reason to go into the past and smash the glass as future me didn't drink from the glass, and so the glass does exist and I drank from it.

And now we hit the instability: If you never smashed Glass A, then Glass A did exist, which means you did drink from it, which means you do go back and smash it. This is not just a paradox. It’s a dynamical inconsistency. The timeline flips back and forth with no stable state.

This paradoxical instability is known as a Grandfather Paradox. I travel back in time and kill my grandfather before my father is conceived. Now that my grandfather is dead, both my father and I don't exist in the future. If I don't exist, I cannot travel back in time and kill my grandfather.

This leads on to one of the major paradoxes within The Terminator movie. It isn't what I consider the perfect paradox, but its a great example of the Grandfather Paradox:

If a Terminator travelled back in time to kill Sarah Connor, John Connor would never exist in the future and hence Skynet would have no reason to send a Terminator back in time to kill Sarah Connor.

Thats a great example of a typical paradox found in The Terminator storyline. There are many but the best paradox by far within the movie is not an example of the Grandfather paradox, it's a Bootstrap paradox, in fact within the movie its a multiple bootstrap paradox.

The bootstrap paradox, so called because of the old saying "To pull onself up by the bootstraps", is a causal loop paradox whereby an object exists only within the loop and has no defined origin.

When I am 30 years old, an old man in a labcoat pops into existence in front of me. He hands me a battered old notebook and tells me that all of the information required to build a time machine is contained in the notebook, but it will take me a lifetime to use the notebook to create it. He then disappears. The notebook is battered and old so I buy a new notebook and copy all of the notes across from the old to the new notebook. I then spend the next 50 years building a time machine. When it is complete, I take my 50 year old notebook and travel into the past to give it to my younger self.

In this instance, no-one has written the notes for the time machine. They are copied from notes from the future and then handed back to me in the past. There is no source for the original concept and invention.

The Terminator story uses this in the most perfect way in a multi-layered bootstrap paradox caused by Skynet sending a Terminator back into the past to kill Sarah Connor:

Skynet sends a Terminator into the past to kill Sarah Connor. The Terminator fails and is destroyed. The Terminator processor is recovered from the wreckage by Cyberdyne Systems and reverse engineered to create the technology that Skynet runs from.

A great example of the Bootstrap Paradox. The technology to build Skynet and Terminators comes from the future. Its used in the past to build Skynet and then Terminators. No-one invents the technology. Its passed from future to past and then developed from past to future.

Skynet sends a Terminator into the past to kill Sarah Connor to prevent John Connor from being born. The human resistance send Kyle Reese into the past to protect Sarah Connor from the Terminator. During their time together, Kyle and Sarah conceive John Connor.
Another great Bootstrap Paradox. John Connor only exists because Skynet sent a Terminator back in time to prevent John Connor from existing.

It's probably worth noting here that even if Kyle and Sarah hadn't conceived John Connor, the myth and lore about Sarah's son John Connor that both Kyle and The Terminator brought from the future to the past would probably have been enough for Sarah to have been picky about the partner that she does conceive John with, name him John and then ensure that he was as prepared as possible to be the leader of the future human resistance.

Any way that you look at it, Skynet really screwed up their own future by sending a Terminator back into the past to kill Sarah Connor.