Connectome (38 page)

At the present time, cryonics is closer to religion than to science, because it is based on faith rather than evidence. Its members believe that a future civilization will be able to resurrect them, based only on their faith in limitless technological progress. The test that I propose is a way of finally bringing some science to Ettinger's Wager. If the vitrified bodies contain intact connectomes, this does not prove that resurrection will be possible. But if connectome death has already occurred, resurrection will almost certainly be impossible.

Many Alcor members might not be eager to see the results of such a test. They may prefer blind belief as a means of consolation about their impending demise. If a scientific test has the potential to uncover factual information refuting their beliefs, they might prefer that the test not be conducted. There may be other members, though, who want evidence over faith, and would demand tests of connectome integrity.

It could turn out that the Alcor members stored in liquid nitrogen are already connectome dead. If so, that would not be the end of Alcor. They could always use connectomics as a means to improve their methods of preparing and vitrifying brains. Short of actually resurrecting their members, this is the only way I can imagine assessing the quality of their procedures. Even if their current method does not prevent connectome death, they could ultimately find one that does.

 

Cryonics is not the only way to preserve a body or a brain for the future. In his 1986 nanotechnology manifesto,
Engines of Creation,
Eric Drexler
proposed that brains be preserved by chemical means. In a 1988 paper modestly titled “A Possible Cure for Death,” Charles Olson
independently proposed the same thing.

What Drexler and Olson were proposing was not a new procedure, but a new use for an old procedure called plastination. You may have seen one of the popular traveling exhibitions of human bodies preserved in plastic. Similar methods have long been used to prepare tissue for electron microscopy. The goal goes beyond merely preserving the look of tissue to the naked eye. Researchers try to leave every cellular detail intact, down to the structure of individual synapses. First, special chemicals like formaldehyde are delivered to cells by circulating them through the blood vessels. These are called fixatives, because they create links between the molecules that make up cells, fixing them in place.
Once reinforced in this way, cellular structures are protected from disintegration. Then the water in the brain is replaced by alcohol, which in turn is replaced by an epoxy resin that hardens in an oven. The final product is a plastic block containing brain tissue (see Figure 53, left).
The block is hard enough that it can be cut thinly with a diamond knife, as we do when finding connectomes.

 

 

Figure 53. Plastination: brain tissue preserved in epoxy
(left)
and insect in amber
(right)

 

Aldehdye fixation, the first step of plastination, is also used by morticians when preserving bodies. This practice is called embalming, and is used to prepare bodies for temporary public display at funerals. In rare cases, the public display doesn't end with the funeral. For example, the Russian revolutionary Vladimir Lenin was embalmed
after his death in 1924, and his body can still be seen in a Moscow mausoleum. It's not clear how long an embalmed body will remain intact. And even if it appears normal, its microscopic structure may be deteriorating. The full plastination procedure preserves biological structures indefinitely. The result looks similar to insects trapped in fossilized amber (Figure 53, right), some of which are millions of years old.

Plastination could be safer than cryonics, because it does not depend on a constant supply of liquid nitrogen. If Alcor goes bankrupt, or some kind of disaster damages its warehouse, the bodies and brains would be jeopardized. But a plastinated brain requires no special maintenance. Charles Olson predicted that “the cost of brain chemopreservation could be less than that of a typical funeral.” There is an important stumbling block, though: Right now, plastination works on only very small pieces of brain. For various technical reasons, no one has yet succeeded in preserving an entire human brain with its connectome intact.

Ken Hayworth recently decided to do something about this. As you'll recall, he invented ATUM, the machine that slices brains thinly and collects them on a plastic tape for imaging and analysis. Many neuroscientists are driven not only by curiosity but also by ambition. Some want to discover something about the brain that will yield their next publication or promotion. Others aspire to win a Nobel Prize. But Hayworth makes all their ambitions look pedestrian.
His
goal is to live forever. As Woody Allen said, “I don't want to achieve immortality through my work. I want to achieve it through not dying.”

Hayworth and his colleagues have established the Brain Preservation Prize, which offers $100,000 to any team that can successfully preserve a large brain in a way that leaves the connectome completely intact. A quarter of the prize money can be won by preserving a mouse brain. This is regarded as a steppingstone to a human brain, which is a thousand times larger in volume.

Hayworth is planning to plastinate his own brain. He would like to do this well
before
he dies of natural causes, while his brain is perfectly healthy. That would best preserve his brain for the future, but, by any ordinary definition, it would also kill him. He may have difficulty finding helpers, because their acts would likely be regarded as assisted suicide. Hayworth argues that plastinating his brain would not be suicide but salvation. It's his only chance at eternal life.

But how do you revive a plastinated brain? Raising the temperature brings cryopreserved sperm back to life. One can imagine thawing the bodies in the Alcor warehouse, but reversing aldehyde fixation and epoxy embedding seems much more difficult. Then again, if a civilization of the future is advanced enough to resurrect the dead, maybe they will also be advanced enough to unplastinate them. Eric Drexler imagined that an army of “nanobots,” robots as tiny as molecules, might be used to unplastinate bodies and brains and repair whatever damage they've suffered. In the twenty-five years since then, nanotechnology does not seem to have moved any closer to realizing his dream.

Hayworth has thought carefully about his plans. If his plastinated brain cannot be revived, there might be an even better alternative. He imagines a future version of his ATUM invention, scaled up to handle a large brain—his brain. Once cut into ultrathin slices, his brain will be imaged and analyzed to find his connectome. The information will be used to create a computer simulation of Hayworth, one that thinks and feels like the real thing. This plan seems even more far-fetched than cryonics. Could it really be feasible?

It's distressing how little they tell us about heaven. We can at least imagine the gates. They are pearly and perched on a cloud. Saint Peter stands guard, ready to make sinners sweat by posing tough questions. But what is it like inside the gates? Everyone wears white. (I'm not sure how I feel about that.) The harp is the only accessory, and angels abound. These snippets of information aren't much to go on. Only recently did I realize why religions might prefer to be vague: People would rather fantasize about their own heaven than have one thrust upon them.

In the world's cultures and religions, conceptions of heaven have evolved slowly throughout history. Late in the second millennium, a radically new one emerged:

 

Heaven is a
really
powerful computer.

 

I don't mean that ecstatic look some nerds get when fondling their laptops. Let's not mistake such fetishism for a sign of spiritual enlightenment. But then again, why do these people spend so many of their waking hours online? Would it be too far-fetched to say that they thirst for transcendence, that they yearn to escape the inadequacies of this body and this world? While online, teenagers can forget the embarrassment of their pimply faces and underdeveloped physiques. People can take a pseudonym, alter their age, or masquerade with a photo of their dog. Netizens are free to be who they want to be, rather than who they really are.

A body chained to a computer, glassy eyes staring at a glowing screen, and fingers pecking away on a keyboard. That's a slightly less corporeal existence, to be sure, but I would only call it purgatory. It's still not what I mean by the new idea of heaven. Some nerds want more. They would like to discard their bodies completely and transfer their minds to computers. The idea of living as a computer simulation has been embraced by science fiction, which calls it “mind uploading,”
or “uploading” for short.

It's not possible yet, but perhaps all we have to do is wait for computers to get more powerful. Video games are stunning proof that computers can simulate the physical world. Every year the scenery looks more detailed and lush; every year bodies move in more lifelike ways. If computers can do that, why can't they simulate minds?

It's no exaggeration to compare uploading with ascension to heaven. Just think about the word itself. “
Up
loading” gets the direction right, as most agree that heaven is located in a high place. Some devotees prefer to say “mind downloading,” but they are in the minority. It's not hard to understand why—“downloading” sounds suspiciously like going to hell.

Like thoughts of a traditional heaven, belief in uploading helps us cope with fear of death. Once uploaded, we would become immortal. But that's just the beginning. In the virtual world, we could beautify and strengthen our bodies simply by reprogramming the computer simulation. No need to suffer at the health club. Or perhaps we'll rise above such superficial concerns and focus instead on improving our minds. Let's not just upload—let's upgrade!

You may protest that uploading does not truly free us from the material world. The computer that runs the simulation might still malfunction or decay. But Christians also teach that the immortal soul does not lack a body in heaven. (Only during the time interval between death and Judgment Day does the soul wander bodiless.) There is still a body, but luckily it's incorruptible, an improved or perfected version.

Likewise, you'd be far better off living in a computer than in a body. Even if Alcor members turn out to be the lucky beneficiaries of bodily resurrection, enjoying the benefits of eternal youth provided by future medicine, they will have to worry about freak accidents that destroy their brains beyond repair. In contrast, the uploaded will feel safe and secure. They can always be restored from backup copies if they happen to be snuffed out by faulty hardware, or by a bug in whatever operating system of the future everyone will love to hate.

Some will no doubt say that all these arguments miss the point. Going to heaven isn't just about leaving one's bodily existence behind. It's about union with God. While uploaders might not get to meet the Christian God, they do expect to enter a new spiritual plane. Inside the great computer in the sky, the uploaded will mingle their lines of code to form a “hive mind,” or collective consciousness. They will finally dissolve the distinction between self and other that lies at the root of evil and suffering, according to Buddhist teachings. With all the memories of humanity at its disposal, but none of the failings, this new superbeing will possess an unearthly wisdom that could be deemed godlike. We will find spiritual sustenance in our union with each other. Uploading will far surpass the Summer of Love and the Age of Aquarius, which bloomed briefly before the flower children grew up to drive BMWs and vote for lower taxes.

Enough about the advantages of uploading. Heaven sounds great. How can I get there? Well, that's a tougher question. As I'll explain in this chapter, only one even remotely plausible method has been proposed so far: simulating the electrical signals circulating in the network of neurons in your brain. A computer powerful enough to handle such a simulation could conceivably exist by the end of this century. To properly wire up the model neurons in the simulation, it would be necessary to find your connectome. Right now we can't envision any way of doing that without destroying your brain in the process. That sounds worrisome, but the Christian heaven thing isn't any better: Getting there almost always requires dying first.
And there is an additional bonus to destructive uploading—it eliminates the troublesome question of what to do with your old self afterward.

For the sake of discussion, let's ignore these issues and simply suppose that your connectome could be found. Would that make uploading possible too? Simulating an entire brain is science fiction right now, but simulating
part
of a brain has been science since the 1950s at least. The models of perception, thought, and memory described in Part II have been formalized in mathematical equations and simulated on computers, although of course with goals less ambitious than uploading. The simulations are meant to reproduce a small subset of the brain's functions, as well as measurements of neural spiking from neuroscience experiments.