Recursion by Blake Crouch
🍅 Introduction:
Recursion refers to a concept in which a previous instance is repeated within its own definition. Mathematically, the factorial function is a classic example of recursion: to calculate the factorial of 5, for instance, one must first calculate the factorials of 4, 3, 2, and 1. In Blake Crouch's novel called Recursion, this idea is ingeniously applied to construct a time travel system, allowing people to recursively relive their lives through their memories. The story explores the fascinating complexities of human memory.
🦉 Characters:
Helena Smith: The main character of the story. Helena is a middle-aged neuroscientist whose work centers around developing technology to preserve human memories and brain function later in life. The device she envisions is called the memory chair, which can store memories outside the brain and replay them.
Barry Sutton: Barry is the deuteragonist of the story, an NYPD detective investigating a new kind of mental disorder called False Memory Syndrome (FMS for short). People suffering from FMS experience vivid and detailed memories of past lives they never actually lived. This often leads them to harm themselves or others due to the overwhelming reality of the situation.
Marcus Slade: Marcus is a businessman who, conveniently, also wants to solve the same problem Helena Smith is working on. By pure coincidence, he shows up just when Helena is most in need of funding to build her memory chair — and also just so happens to have the lab and resources perfectly suited for the task.
🧠Time Travel:
In Recursion, time travel occurs through Helena’s “memory chair“. The chair stimulates the brain using a combination of chemicals and electromagnetic pulses to activate and enhance the hippocampus—a region crucial for memory storage and recall. By flooding the brain with specific neurotransmitters, such as dopamine and norepinephrine, and recreating the neural patterns associated with a particular memory, the chair enables users to relive (literally) that memory. For this to work, the memory must be exceptionally strong, as the chair maps the brain and replays the memory with heightened precision in the presence of these neurotransmitters. The process is so immersive that it transports the user’s consciousness back to the moment being recalled, effectively allowing them to relive and even alter past events, just like a recursive algorithm.
⛺ The Plot:
Helena’s mother suffers from Alzheimer’s and is losing her memories. This becomes the major motivation for Helena to build the memory chair — a device that can store memories in a vessel outside the brain and manually replay them. Her hope is to save people from losing their sense of self to this devastating disease.
Out of nowhere, a billionaire businessman named Marcus shows up with a pile of money and a remote laboratory, offering Helena the resources she needs to finally build the memory chair.
But Marcus knows things about Helena and her project that he shouldn’t. He also seems to have a strange gift for predicting how events will unfold. So maybe there’s a deeper reason why he chose Helena and her work to invest a huge chunk of his fortune into.
Helena successfully builds the memory chair — but it doesn’t just store and replay memories; it allows people to travel back into their own past, reliving and altering their lives. Marcus uses the technology selfishly, manipulating events for power and control.
The memory chair’s use causes False Memory Syndrome (FMS) to spread worldwide — people wake up with vivid memories of entire alternate lives they never lived, creating mass confusion, violence, and societal collapse. Basically, the machine changes timelines to write new ones, and memories from different timelines sometimes seep into the current timeline.
NYPD detective Barry Sutton, investigating an FMS-related suicide, gets drawn into the mystery. Barry eventually experiences memory travel himself and discovers the horrifying truth about the memory chair’s impact on reality.
Barry and Helena team up to try to undo the damage — but every time they attempt to fix things by going back, they create new timelines and new problems. They realize they are stuck in an endless loop of resetting the world, never fully solving the problem.
Helena figures out that the only way to truly stop the chaos is to prevent the memory chair from ever being built. As a result, FMS never happens, reality stabilizes, and people’s lives proceed naturally — but at the cost of Helena and Barry’s shared memories and experiences with each other being erased.
In the final moments, Barry and Helena meet again as strangers — hinting that, even across erased timelines, something between them remains.
