Editor's note: This segment was rebroadcast on May 9, 2022. Find that audio here.
Neuroscientist David J. Linden is dying.
But the impending end of his life doesn’t mean he’s done learning about the human mind just yet. Linden was recently diagnosed with terminal cancer. In a piece in The Atlantic, he writes: "I may be dying, but I'm still a science nerd."
During a routine echocardiogram, doctors noticed something sticking up next to Linden’s heart that they thought was a hiatal hernia or a benign growth called a teratoma, he says. After the tumor was removed, a biopsy found it was a form of malignant cancer called synovial sarcoma that had grown into the wall of his heart — making it impossible to remove.
One way the biomedical researcher at Johns Hopkins University School of Medicine processes his diagnosis is by nerding out about it. His doctors showed him photos of his tumor and heart surgery to his excitement.
“It is empowering to be a nerd about something really grim, meaning my own terminal cancer,” he says. “But I think the more interesting thing is what it has led me to think about the human mind.”
After his diagnosis, he writes that feelings of anger about his shortened time came alongside gratitude for his love, relationships and career in neuroscience.
The fact that the human brain can occupy two mental states at once may be obvious for most people, Linden says, but it took his diagnosis for him to realize it.
In neuroscience, researchers believe people have a specific mental state at a given moment: sleepy or alert, exploring or pulling back.
“In truth, you can occupy more than one cognitive state at once, even if these states at first blush would seem to be contradictory,” he says, “like in my case, are gratitude and anger.”
Linden writes that there is no objective human experience: “All that we perceive and feel is colored by expectation, comparison and circumstance.” One example of this is people’s relative conception of time.
Time drags on while you wait in line at the Department of Motor Vehicles, he says, but it flies when you’re having a beer and conversation with a friend.
“All of our human perception is constructed. There is no objective experience in the world,” he says. “It's all colored by our mood and our expectations.”
The concept of five years can feel different depending on where you are in life, he writes. One might think five years has a fundamental value that can’t change, but he knows that’s not the case.
“If someone had told me before my diagnosis that I had five years left to live, I would have been feeling deeply cheated and offended,” Linden says. “But now, with my prognosis of six to 18 months of life to live, the idea of five more years seems like an impossible gift.”
The human brain isn’t wired to comprehend our own death — that we will someday no longer exist, he says.
Linden can practically deal with his impending death by finalizing his will, getting his finances in order and writing recommendations for his trainees to help further their careers after he’s gone. But he finds himself failing to “deeply engage” with the idea of a world without him, he says.
“My mind skitters over the surface of this, and I don't think that's a personal failing,” he says. “I think it is telling us something about being human.”
When Linden entered the neuroscience field 43 years ago, he learned that the brain is reactive: Humans use their senses to make decisions about the world around them. One recent advancement in the field is the knowledge that the brain is always active and predicting the near future.
The brain spends a lot of time trying to figure out if other people are friends or enemies, or whether hunger is approaching, he says.
“The idea that the brain is constantly working to predict the near future presupposes that there will be a near future,” he says. “And I think in this way, our brains are hard-wired to have a problem with truly engaging with our own demise.”
Linden has been pondering questions about immortality and how our inability to engage with our own deaths has influenced human history in the form of religion. Almost all of the world’s major religions believe in an afterlife, reincarnation or some form of an “immortal soul” that lives beyond the demise of the body, he says.
“What I suspect is … that this is a result of the fact that our brains are hardwired to continuously predict the future and thereby to make it very difficult for us to imagine ourselves gone,” he says. “I think that this is the way this manifests in the species, the way it manifests societally.”
Considering the extent of religion’s impact on human society, it’s “astonishing” to think about how much this one aspect of the brain has molded humanity, he says.
Taking a step back and observing the human mind in this way gives Linden comfort in his final days.
“To me, thinking about the way my own impending death informs me about the human mind is a way for me to take control of my situation — to feel a sense of agency — rather than just being passive and borne along by this medical problem,” he says. “I feel that it's given me a way to engage, to think to the end. And that's an enormous gift.”
This segment aired on January 17, 2022.