While recording our previous podcast (AN: At the time of this writing, a discussion-based podcast was running), we’d been discussing things like causal loops and other time paradoxes, which spurred SurpriseEnema to mention The Lake House. Our curiosity was piqued, so Fern, doorXmouse, her partner and I decided to watch it for the first time. Well, we did. We watched it. That is a thing that happened.
I’m not here to talk about whether The Lake House is a good or bad movie as a whole. Is it a bad film? I don’t know. Maybe not. I certainly didn’t feel a strong negative reaction to it. By the end of the night, I didn’t regret having watched it.

The titular house and the strangely non-titular mailbox.
It may be important to establish that they can actually see the little red flag on the mailbox rise and fall when the mail has been sent or delivered, so we know that this thing has set rules. Really, the mailbox itself is pretty logical, so long as we disregard any questions as to how it works (which we should). I have no intent on contemplating hypotheticals such as “What would happen if Kate put a bomb in the mailbox and sent it into the past?” (although, seriously what would happen?). The problem with the film is the inconsistency with which time travel is presented. You’d think that someone writing a script or novel or game or what-have-you that revolves around time travel would take special care to laying out rules for how time works in their prospective universe. Unfortunately, it doesn’t usually seem to happen that way. And so, it didn’t happen that way with this movie.
It should go without saying that this article will contain massive spoilers.
1. Ontological Paradoxes
The reason why we started watching The Lake House is because we were under the impression that it was a story about ontological paradoxes, also known as causal loops or bootstrap paradoxes. In case you didn’t listen to our podcast, I’ll explain what those are. An ontological paradox involves two events, one in the past and one in the future, which are caused by each other, thus forming a loop with no discernible origin point. An example would be this: You receive a journal full of instructions for building a time machine. Months later, following the instructions, you have built the time machine. You use it in order to go back in time, copy the instructions into a fresh, blank journal, and leave that journal for your younger self. The result is that the instructions have no discernible origin – how does the knowledge for building a time machine even exist if the only reason why you have it is because you merely copied the knowledge from a book that you wrote by copying a book that you wrote by copying a book, ad infinitum? These things are really interesting to think about.
Anyway, having watched this movie, I found only one arguable instance of an ontological paradox, and a mild one at that. In the beginning of the film, Kate mentions in her letter that the previous occupant left behind a box of stuff in the attic. Much later, when Alex decides to take leave of the house, he seems to remember this and intentionally places a box full of stuff in the attic for her to find in the future. Thus, the box is there because he knows that, in the future, the box is supposed to be there. It’s a self-fulfilling loop.

This attic is the first and last place where time seems logical in this movie.
Furthermore…
2. Timeline Stability
In the same, first letter in which Kate mentions the box in the attic, she also mentions a trail of pawprints running down the walkway. After having read the letter, while painting the walkway in the past, Alex witnesses his dog, Jack, running through the paint… leaving pawprints behind. This isn’t really an ontological paradox because nothing Kate said influenced the dog to run through the paint, but it’s important to note here because it follows the same logic: Someone from the future mentions an event which occurred in the past, and it doesn’t change history or cause a butterfly effect or something.

The ruin caused by these pawprints is an accurate representation of how stable time is in this universe.

It’s unclear whether Alex’s disembodied hand appeared in the future and wrote on this wall.