Thanks to some instruction from the delightfully woo-woo self-help book The Artist’s Way, I began penning a couple stream-of-consciousness pages in my notebook each morning, and the new habit led me to a potent discovery. When I saw my thoughts written out in ink, it was entirely obvious that my worries had scant connection to reality. I was either worrying about events that were unlikely to happen, things that were ultimately trivial, stuff that was entirely out of my control, or all of the above. This insight brought an unexpected benefit. When I noticed that I was worrying about nothing, I stopped worrying so much. This written copy of my thoughts was pure gold—because who doesn’t want to worry less?

All of this raised a major question, though. Instead of scribbling my thoughts, which was impossible to do for more than a few minutes a day, why couldn’t I simply record them right from my brain waves? I imagined bidirectional earbuds and an iPhone that could convert a slew of inner qualms into a tidy transcript. I logged into the App Store to see if such a thing was available—but, no, there’s no app for that.

I recalled reading about a team of researchers at the University of California, Berkeley, who figured out how to decode the pictures in our heads by scanning brain waves.

So I decided to reach out to these neuroscientists and find out how close we are to having this technology at the touch of a clammy fingertip.

It turns out that the scientific community is working on the question of how to translate neural activity into words—but the issue is complex. The human brain contains around one hundred billion neurons that are linked to one another in roughly one hundred trillion (that’s 100,000,000,000,000) neural connections. Imagine all your power cords hopelessly tangled and knotted together… then multiply that by twenty trillion. And that’s just your brain’s hardware. Now think of your mind—your thoughts, your conscious experience of the world around you—as the software running on that hardware. It’s the software that scientists will have to decode in order to capture our thoughts, but they can only get at it through the hardware. As Dr. Mara Breen of Mount Holyoke College explained to me, scientists don’t entirely understand how the hardware gives rise to the software of our lived experience.

In the past few years, there have been some incredible leaps forward in what’s called “neuro mind reading” and related technologies. Even without fully understanding the interplay of the hardware and software, a group of researchers at the University of Utah succeeded at translating the brain signals of paralyzed but conscious individuals into words. They did so by placing microelectrodes directly on the part of the cerebral cortex that’s known to be associated with language and then instructing their patients to repeatedly read certain words. The researchers then recorded the associated neural activity and built a rough lexicon linking the words to their brain signals. That allowed them to read patients’ brain waves and make out some of the words they were thinking.

Dr. Bradley Greger, one of the researchers who worked on the project in Utah, told me by email that his goal is to help restore function to individuals who have lost capability through injury or disease. To that end, he and a team at Arizona State University recently developed a prosthetic limb capable of bidirectional communication with the brain. The wearer operates the prosthesis simply by thinking about it, and the prosthesis sends information back to the brain to confirm that the limb has moved as directed.

In their efforts to translate patients’ neural activity into words, Dr. Greger and his team were successful because they had placed microelectrodes directly on the brain’s surface, something they could do only because those subjects also happened to be having brain surgery. “Finding the appropriate patient to work with on that project is very rare,” Dr. Greger told me. Progress has been slow.

Many other scientists use functional magnetic resonance imaging, or fMRI, for their work because it’s noninvasive. A lab at UC Berkeley has successfully used fMRI to decode and reconstruct the pictures we see in our heads. For this task, researchers recorded their subjects’ brain waves while they watched hours of YouTube clips inside an fMRI machine and then built a database to correlate neural activity with specific imagery—once again, a sort of dictionary of the brain. Then they put their subjects back in the fMRI for more YouTube viewing, and this time they were able to partially reconstruct the viewed images based solely on neural activity.

In a recent radio piece, Dr. Jack Gallant, the Berkeley professor at the helm of this research, casually described the exact invention I was seeking: “To my mind,” he said on a Sunday news program, “the most interesting decoder that we can create… is something that would decode internal speech, the little man or woman in your head that talks to you all the time.” Immediately, I fired off an email asking if such a decoder is really in the works.

“There are around twenty billion neurons in the cerebral cortex, and each neuron can fire up to around one hundred times per second,” he wrote in reply. “fMRI only measures about fifty thousand points across the cortex.” In other words, scientists are majorly limited by their measurement tools. “When we can measure the brain better… we can build a better decoder,” he said. “So as long as science progresses and builds better methods for brain measurement, there will inevitably along with that come better brain decoding, and eventually, somewhere down the road, twenty years, fifty years, who knows, there will be some new technology developed that will allow you to decode internal speech.”

The quality of scientists’ tools isn’t even the only complicating factor. According to Dr. Breen of Mount Holyoke, a cognitive scientist, “There are a lot of other questions that go along with [recording your thoughts]. For starters, how do you know all these thoughts are in words?”

I was surprised by the question. I felt certain that my thoughts are in words because I experience them that way. Soon Dr. Breen and I were volleying back and forth on the nature of thought. I quickly conceded that while some of my thoughts seem definitively verbal, others are a bit fuzzier. On this point, Dr. Gallant of Berkeley noted that inner speech is merely one kind of thought and that “of course there are many other kinds of thought and internal mental imagery that do not rely on language.” Given this complexity, Dr. Breen explained that decoding inner narrative isn’t just a question for neuroscientists but also for linguists, philosophers, and cognitive psychologists.

Then she asked the question that changed everything.

“When you imagine a tiger, can you count the stripes on that tiger?” she said, paraphrasing a query posed by the cognitive scientist and philosopher Daniel Dennett.

“And if you can’t, what is it?”

There was no way I could count the stripes on my imaginary tiger.

Later, as I reflected on the incompleteness of the tiger in my head, I realized the significance of what Dr. Breen was suggesting: thoughts don’t have all their stripes. Thoughts, I realized, are like half-striped tigers moving through the wilds of consciousness.

And yet I was a slave to them. My very well-being rose and fell with whatever ill-defined notions were presently firing in the one hundred billion neurons and across the one hundred trillion neural connections of my brain, even when they were only one step better than gibberish. That is a frightening thought.

I went back to Dr. Breen. “Is it possible that we’re walking around constantly misinterpreting our own feelings—or just getting worked up about some, like, half-thoughts that we never understood in the first place?” I asked.

“Absolutely,” she said. She told me about a study showing that we can misread a sensation you might think is as clear as a Windexed window: a perceived feeling of sexual arousal. For this experiment, an attractive female interviewer intercepted males who were crossing a wobbly suspension bridge that ran two hundred feet above a rocky river. The interviewer purposely stopped men who were showing signs of fear (such as clutching the handrail and walking very slowly) and asked them to take a short test. The test asked for a rating of how fearful they thought the average person would be while crossing the bridge and assessed their level of sexual arousal by asking for an interpretation of ambiguous pictures. Then the good-looking female interviewer tore off a corner of paper, wrote down her phone number, and told each subject that he could call her if he wanted to talk about the test he’d taken.

The study was repeated in controlled settings, including on a sturdy bridge instead of a scary one, with the goal of determining whether or not the sensation of fear affected subjects’ perception of their sexual arousal. As it turned out, far more males from the scary bridge called the female interviewer. Results from the written test also indicated that fear of the bridge led subjects to draw sexual inferences from vague cues. It was a clear indication that the subjects conflated the physiological effects of fear, such as an elevated pulse and sweaty palms, with sexual attraction.

In short, we can’t distinguish fear of a suspension bridge from feeling horny.

Dr. Breen explained that the brain is basically a massive pattern-recognition machine. Through repeated auditory cues, for instance, babies learn that a cup is a cup. In all our waking hours, our senses gather information about the world around and within us, and then our brains filter that information through the lens of all the patterns we’ve previously detected. The life experiences of the men on the suspension bridge had taught them to equate the perception of an attractive woman with sexual arousal. On the bridge, they found themselves experiencing signs of arousal and, simultaneously, observing an attractive woman. Thus they were more likely to call the number she gave them, as compared to men on a sturdy bridge, because they perceived themselves to be attracted to her.

“So we suck at understanding our thoughts,” I said.

“Well, not exactly,” said Dr. Breen.

While it was accurate to say that the men experienced physical arousal because of the conditions on the suspension bridge, we couldn’t conclude that they didn’t “really” feel attracted to the woman. Researchers in the 1960s suggested that cognition performs a “steering function.” That is, we’re continuously receiving cues from the world and from our bodies; our cognition then assesses that information and decides whether to label our interior sensations as “joy” or “anger” or “might-poop-my-pants fear of this stupid bridge.” There is no “correct” interpretation of our feelings and thoughts; they exist only insofar as we interpret them.

“This leads to an important theory about depression,” said Dr. Breen. She said that some people fall into thought patterns that facilitate depression, such as a sensation of helplessness, which arise from past experiences. The point of therapy as a treatment for depression is often to help people create new thought patterns.

“Because the thoughts you have change the thoughts you have,” Dr. Breen finished, nodding for emphasis.

I wrapped up the interview before we opened any vaster areas for exploration. It seemed that I hadn’t found the answers I was seeking—and, subjective or not, I was feeling bummed.

I’d started this investigation because I spent so much time worrying about rubbish, but this seemed far worse. It’s not just that we’re worrying about rubbish; it’s that we don’t even really know what we’re worrying about, or why. Some soupy neural activity just sends us down one path or another. Even as the invention was at least decades out, the would-be brain decoder now appeared more important than ever. Besides promising invaluable therapies for the sick and injured, as Dr. Greger was committed to developing, brain decoding would offer a lifeline to anyone afflicted with the condition of the human mind.

Or would it?

Given that thoughts are a jumble of fragments and pieces, it occurred to me that a recorded transcript of those jumbled pieces actually might not be very illuminating. It might not even be intelligible. Meanwhile the (admittedly much more arduous) process of writing down my thoughts had been surprisingly enlightening. In one swoop, my brain was capable of detecting the patchy notions swirling in my mind, filling in their gaps to make them whole—that is, adding the stripes—and then evaluating them for their credibility and value, or lack thereof.

In other words, my own brain was a brain decoder. It required a lot more effort than merely using a digital recorder as I’d imagined, but it was also a whole lot more sophisticated—say, a trillion times more—than anything scientists have conceived of inventing.

Dr. Henry Markram, neuroscientist and director of the Human Brain Project in Switzerland, wrote in Scientific American that “the human brain, an information processor within our skull… is perhaps unparalleled anywhere in the universe.” The statement echoed in my head.

Maybe we already have the greatest mind-reading technology that humankind will ever know. The problem is that it’s powerful beyond comprehension.