The dream of the cyborg is coming true at an exhilarating rate.
As humans gets better and better at making machines, we keep attaching those machines to our bodies to make ourselves better humans.
It seems at times that the only question left is if we can put a human brain in a robotic frame. Actually, it's not a matter of if. It's a matter of when.
This week, social psychologist Bertold Meyer's been travelling around the country with a contraption that looks like a cross between a Halloween mask and Johnny Number Five.
It's the subject of a new documentary by the Smithsonian Channel called The Incredible Bionic Man.
Meyer makes for a great spokesman, since he was born without the lower part of his left arm and now wears a bionic prosthesis. He is, by definition, a cyborg - but only partially.
So just how close are we to a fully formed cyborg? And even more curiously, what will it look like?
WHAT IS A CYBORG?
Let's take a second to agree on what exactly it means to be bionic and what it means to be a cyborg.
In many ways, the two words are interchangeable, and both came into usage around the same time in 1960s.
Whereas "bionic" borrows the "bi-" from biology and "-onic" from electronic, "cyborg" is a portmanteau of cybernetic and organism. Both refer to living organisms that are aided or enhanced by artificial means.
Often these means amount to electronic or mechanical devices, much like the mind-controlled prosthetic hand that Meyer wears on his left arm.
For now, let's just stick with cyborg for simplicity's sake.
The term "cyborg" probably brings to mind images of Robocop or Darth Vadar. But in fact, it doesn't have to be so extreme.
When Manfred Clynes and Nathan S. Kline coined the term in a 1960 article about "altering man's bodily functions to meet the requirements of extraterrestrial environments," they explored chemistry as much as they did mechanical engineering.
In this sense, even Lance Armstrong was a cyborg back in his juicing days.
But for all intents and purposes, cyborgs these days use machines to help them regain lost capabilities - like amputees returning from Afghanistan - or to gain new ones - like soldiers armed with exoskeletons.
OUR CURRENT CAPABILITIES
Those examples in mind, you have to admit that sometimes it feels we live in a sci-fi reality. But that's only because we do.
The so-called incredible Bionic Man that Meyers paraded around Washington DC represents the sum of cyborg parts that have been in development for over half a century, many of which showed up in science fiction books in the interim.
All things told, this TV-ready cyborg has between 60 and 70 per cent of the function of a human being. It even has blood. But blood does not a cyborg make.
To begin thinking about what it might mean to have a fully formed cyborgs, let's go through our current capabilities in cyborg tech - starting with our most advanced capabilities.
The robot featured in the Smithsonian documentary has the same model of prosthetic arm as Meyer, mechanical marvel made by Touch Bionics.
He can move each of the fingers by activating two electrodes that connect to muscles in the residual limb. This is hardly as good as it gets, though.
The latest craze in prosthetics and, by proxy, cyborg technology involve mind-controlled limbs.
DARPA's developed a prosthetic arm that uses targeted muscle reinnervention (TMR) to enable amputees to move robotic limbs merely by thinking about it.
This requires doctors to reattach severed nerve endings to different muscles in the arm, so that when the amputee wants to move his arm, he just thinks about moving his arm.
We saw similar technology in action earlier this year, when the world's first fully mind-controlled leg arrived.
Thanks to an Army-funded project, a Chicago man was able to walk normally years after he'd lost his leg in a motorcycle accident.
Sensors on the mechanical leg are linked to two nerves in the man's hamstring and enable him to walk up stairs and stroll through the park. It looks a little bit futuristic, but hey, wouldn't it?
For the most part, bones are pretty easy. Just about anything from a tibia to a vertebra can be built out of artificial materials like titanium, and has been for a while now.
More recently, techniques for creating artificial bones have improved.
We can grow new bones using plastics and stem cells.
We can also print new bones using 3D-printing technology - this guy got a new skull that was almost completely 3D-printed.
You don't have to replace the bone entirely to enter the cyborg arena. Using titanium foam to make bones stronger, for instance, amounts to a cyborg-like enhancement.
Along those lines, it's also worth mentioning that your friend who got a metal plate in her leg after breaking it is technically a cyborg.
Then again, so is your friend who wears glasses.
The plight of the cyborg gets a little more complicated once we move to things like internal organs, which have proved more difficult to replicate.
Artificial hearts exist but are used more as stop gaps to help patients survive long enough for a transplant, although the technology is constantly improving.
Things get even more complicated - but promising - from there.
Doctors have successfully built an artificial stomach, but it's hardly practical.
Scientists have developed artificial liver cells, but they haven't actually managed to build an artificial organ.
Artificial intestines are still in the works.
An artificial bladder, spleen, lymph system, gallbladder - these are all still to come. As is the most complex organ of them all: the brain.
This is a tough one. The (very long) quest to build an artificial brain can be divided up into two parts: recreating the brain's architecture and perfecting artificial intelligence.
Engineers are constantly coming up with new supercomputers that mimic the brain's neural network.
Some have as many as 530 billion neurons, a healthy amount compared to the average human brain's 86 billion neurons.
Some graduate students showed off a one-million neuron model that can make calculations just as fast as the brain, albeit briefly.
Building a neuron network isn't the same as building a brain, though. You have to make the thing think.
The challenge of making a cognisant machine has proved to be incredibly difficult, and even though we're seeing artificial intelligence in more and more everyday applications (think: Siri) we don't yet have a way to make machines completely think for themselves.
We do have artificial brains that can solve problems on their own, but creating something of the same complexity as the human brain might be impossible.
SO ABOUT THAT FULL-FLEDGED CYBORG...
Let's just assume, for the sake of simplicity, that we're not going to build an artificial brain.
It might be impossible, but it's certainly very difficult since scientists using a supercomputer with 83,000 processors could only mimic 1-per cent of the human brain's activity.
Brains are really, really complicated.
Plus, if we build an artificial brain, is the bionic man even a man any more?
A pinnacle of cyborg technology, however, would be everything but the brain. Put simply, this version of a full-fledged cyborg would be a brain and a body completely made up of mechanical parts.
Remember Krang from the Teenage Mutant Ninja Turtles? It would be something like that.
To get a better idea of how possible this would be, understanding the current state of prosthetics and artificial organs, we talked to cyborg expert Tim Maly (Maly curated the Tumblr "50 Posts About Cyborgs" - you should definitely check out).
Maly's point was very simple. There's no way we're going to have a completely cybernetic human being with the materials we're currently using.
"It probably won't be a mechanical body," Maly told Gizmodo. "It will probably be some biogrown body, and it won't be recognisably to us as Robocop, because it'll already be part of a long line of small improvements."
So instead of a shiny robotic shell, our cyborg might just get lab-grown flesh. That's probably ok, though. He'd fit in better.
THE INEVITABLE ETHICAL CONUNDRUM
Asked how long it would take for this biogrown body, Maly couldn't say.
Obviously, there are a host of ethical questions to be answered about how much enhancement is too much.
Few people are comfortable with the idea of man playing God, and once we start building superhuman cyborgs, we're definitely entering that territory.
That in mind, it's probably safe to say that we'll build a full-fledged cyborg when we're ready to, not just technologically ready but socially, politically, and religiously as well.
It's very difficult to say when the ethical piece of the puzzle will fall into place. It could be decades, and it could be a century. But the ethical debate should progress alongside technology.
This is all to say that if you're looking forward to a future of chrome-coated cyborgs, just keep reading those science fiction novels.
Here on Earth, it'll be a little bit more familiar.
"We're only at the very dawn of that techno biological revolution," Maly concluded about our hypothetical full-fledged cyborg, "but I feel - at risk of ending up on Paleofuture in 10 years - I feel like it's much more likely that anything like that is going to come from biotech."