Elon Musk wants to merge the computer with the human brain, build a "neural lace," create a "direct cortical interface," whatever that might look like. In recent months, the founder of Tesla, SpaceX, and OpenAI has repeatedly hinted at these ambitions, and then, earlier this week, The Wall Street Journal reported that Musk has now launched a company called Neuralink that aims to implant tiny electrodes in the brain "that may one day upload and download thoughts."

And he's not the only one. Bryan Johnson, a Silicon Valley entrepreneur who previously sold a startup to PayPal for $800 million, is now building a company called Kernel, pledging to fund the operation with $100 million of his own money. He says the company aims to build a new breed of "neural tools" in hardware and software—ultimately, in a techno-utopian way, allowing the brain to do things it has never done before. "What I really care about is being able to read and write the underlying functions of the brain," says Johnson.

In other words, Musk and Johnson are applying the Silicon Valley playbook to neuroscience. They're talking about a technology they want to build well before they can actually build it. They're setting the agenda for this intriguing yet frightening idea before anyone else sets it for them. And they're pumping money into the idea in ways no one else ever has. Throw in all those science fiction tropes involving brain interfaces—that's where the term "neural lace" comes from—and you've got a brand new and potentially very important industry that's ridiculously difficult to make sense of.

Let's start here: According to David Eagleman, a Stanford University neuroscientist and an advisor to Kernel, the notion of implanting a computer interface in a healthy human brain is a non-starter—not only now, but even if we look many, many years down the road. "With any neurosurgery, there's a certain risk—of infection, of death on the operating table, and so on. Neurosurgeons are completely reluctant to do any surgery that is not a required surgery because the person has a disease state," he says. "The implanting of electrodes idea is doomed from the start."

That said, surgeons have already implanted devices that can help treat epilepsy, Parkinson's, and other maladies with what's called deep brain stimulation. In these situations, the risk is worthwhile. Researchers at IBM are exploring a similar project, analyzing brain readings during epileptic seizures in an effort to build implants that could stop seizures before they happen.

The immediate aim of Kernel and, apparently, Neurolink is to work with devices along the same lines. Such devices would not only send signals to the brain as a means of treatment, but also gather data about the nature of these maladies. As Johnson explains, those devices could also help gather far more data about how the brain works in general—and ultimately, could feed all sorts of other neuroscience research. "If you have much higher quality neural data from more regions of the brain, it will inform all sorts of other possibilities," Johnson says. "We just haven't had the right tools to acquire these datasets."

As Eagleman explains, this could not just fix unhealthy brains, but get more out of healthy ones too. "In these situations where you have reasons to open the head anyway," he says, "then you can look for ways of improving the brain."

What Johnson and presumably Musk hope to do is gather data that could, years and years down the road, help us build a kind of interface that lets humans connect their brains to machines. Musk believes this kind of thing will help us keep pace with artificial intelligence. "Under any rate of advancement in AI, we will be left behind by a lot," he said at a conference last summer. "The benign situation with ultra-intelligent AI is that we would be so far below in intelligence we’d be like a pet, or a house cat. I don't love the idea of being a house cat."

But Eagleman is adamant that this kind of interface will not involve implanting devices in healthy brains. And you hear much the same from others working in the field. Chad Bouton, a vice president of advanced engineering and technology at the Feinstein Institute of Medical Research, which is working to develop bioelectronic technology for treating disease, also warns that brain surgery is an incredibly invasive procedure.

It is far more likely, Eagleman says, that scientists will develop better ways of reading and simulating the brain from the outside. Today, doctors use techniques like functional magnetic resonance imaging, or fMRI, to read what's happening in the brain, and they use methods like trans-cranial magnetic stimulation to change its behavior. But these are rather crude techniques. If scientists can better understand the brain, Eagleman says, they could potentially improve these methods and build on them, creating something far more useful.

Researchers could also develop genetic techniques to modify neurons so that machines can "read and write" to them from outside our bodies. Or they could develop nano-robots that we ingest into our bodies for the same purpose. All this, Eagleman says, is more plausible than an implanted neural lace.

If you strip away all the grandiose language around these efforts from Johnson and Musk, however, Eagleman admires what they are doing, mainly because they are pumping money into research. "Because they are wealthy, they can set their sights on a big problem we're trying to solve, and they can work their way toward their problem," he says.

That doesn't sound quite as revolutionary as a neural lace. But it's also not quite as frightening. And, well, it's a lot more real.

Correction: This story has been corrected to properly identify functional magnetic resonance imaging.