Connectome (41 page)

But computers have forced us to reexamine the doctrines of materialism and mechanism. “You are a bunch of information,” uploaders believe. You are neither machine nor matter. Those are just means of storing what you really are—information. In our everyday experiences with computers, we have learned to distinguish between information and its material incarnation. Suppose I take your laptop computer and, overcome by a murderous rage, hack it to pieces. You retrieve its carcass and manage to pull out its hard drive, which is still in good shape. You don't have to mourn long. Just transfer the information to another laptop, and we can go about our lives as if nothing ever happened.

Uploaders don't see a fundamental difference between humans and laptops. They think it should be possible to transfer the information of your personal identity into some other material form. The uploader chides the materialist by saying “You are not your atoms, but the pattern in which they are arranged.” The uploader rebukes the mechanist with “You are not your neurons, but the pattern in which they are connected.” Although a pattern requires matter for embodiment, it belongs to the abstract world of information, not the concrete world of matter.

Indeed, the uploader might say that your new laptop is the
reincarnation
of your old laptop. The transmigration of your laptop's soul occurred when you transferred the information in the hard drive. And so we are led to the idea that
information is the new soul.
We've come full circle, returning to the idea that the self is based on a nonmaterial entity, something that is ghostlier than matter.

The analogy is not perfect. Unlike the soul, which is usually regarded as immortal, information can be lost permanently. The nanotechnologist Ralph Merkle
has defined the concept of
information theoretic death
as the destruction of the information about personal identity stored in the brain. Returning to our laptop example to illustrate his idea, suppose that the original hard drive from your damaged computer is recovered, but that its motor was damaged during the rampage. It's beyond your technical capabilities to transfer the information to your laptop. But someone with superior nerdly powers might be able to fix the motor so that you can perform the transfer. On the other hand, if I were really mean, I could have passed a powerful magnet over your hard drive, instead of chopping up your computer. This would have erased the information on the hard drive, which is stored in a magnetic pattern. In that case, no technology, no matter how advanced, could recover your information. It's fundamentally impossible.

Merkle's definition of death is of more philosophical than practical importance. To apply it, we need to know exactly how memories, personality, and other aspects of personal identity are stored in the brain. If this information is contained in the connectome, then information theoretic death is nothing more than connectome death.

All efforts to achieve immortality can be viewed as attempts to preserve information. Most humans would like to have children before they die. Some of the information in their DNA will survive in their children's DNA, and other kinds of information will survive in their children's memory. Some humans try to achieve immortality by writing songs or books that will be remembered by future generations. This is yet another attempt to embed information about themselves in the minds of others.

Cryonics and uploading seek to preserve the information in brains. They can be viewed as part of a broader movement called transhumanism, which seeks to transform the human species. We no longer have to wait for the glacial course of Darwinian evolution, say the transhumanists; we can use technology to alter our bodies and brains. Or we can discard them completely, and migrate to computers.

Transhumanism has been ridiculed as the “rapture of the nerds.” Some find it strange to fantasize about eternal life in the future when so many dire problems threaten the world today. But transhumanism is the inevitable and logical extension of Enlightenment thought, which exalted the power of human reason. Emboldened by their successes in mathematics and science, European thinkers sought to establish law and philosophy on principles deduced from rational thought, rather than appealing to tradition or revelation from God. The philosopher Leibniz even believed that all disagreements arose from mistakes in reasoning, and suggested that they could be resolved by formalizing arguments with symbolic logic.

But in the twentieth century the limitations of reason became painfully apparent. The logician Kurt Gödel proved that mathematics is incomplete, because there exist statements that are true but cannot be proved. The physicists who pioneered quantum mechanics discovered that some events are truly random and cannot be predicted even with infinite information and computational power. If reason fails even in mathematics and science, how can we expect it to succeed elsewhere? Indeed, many philosophers have become convinced that morality cannot be derived from reason; they call attempts to do so the “naturalistic fallacy.”

Transhumanists no longer believe that reason can answer all questions. Yet they still believe in its supremacy, because of its power to continually create more advanced technologies. Transhumanism resolves a major problem of the Enlightenment, which was based on a scientific worldview that deprived many people of the feeling of purpose. If physical reality is just a bunch of atoms bouncing around, or genes competing to replicate, then life may seem meaningless. In his book on the Big Bang,
The First Three Minutes,
the theoretical physicist Steven Weinberg wrote, “The more the universe seems comprehensible, the more it also seems pointless.” This viewpoint was expressed more poetically by Pascal in his
Pensées:

 

I see those frightful spaces of the universe which surround me, and I find myself tied to one corner of this vast expanse, without knowing why I am put in this place rather than in another, nor why the short time which is given me to live is assigned to me at this point rather than at another of the whole eternity which was before me or which shall come after me. I see nothing but infinites on all sides, which surround me as an atom and as a shadow which endures only for an instant and returns no more. All I know is that I must soon die, but what I know least is this very death which I cannot escape.

 

The “meaning of life” includes both universal and personal dimensions. We can ask both “Are we here for a reason?” and “Am
I
here for a reason?” Transhumanism answers these questions as follows. First, it's the destiny of humankind to transcend the human condition. This is not merely what will happen, but what should happen. Second, it can be a personal goal to sign up for Alcor, dream about uploading, or use technology to otherwise improve oneself. In both of these ways, transhumanism lends meaning to lives that were robbed of it by science.

The Bible said that God made man in his own image. The German philosopher Ludwig Feuerbach said that man made God in his own image. The transhumanists say that humanity will make itself into God.

It's time to return to reality. We've each got one life to live, and one brain to do it with. In the end, every important goal in life boils down to changing our brains. We are blessed with natural mechanisms for transformation, but we find their limitations frustrating. Beyond appealing to our curiosity and sense of wonder, can neuroscience give us new insights and techniques for changing ourselves?

I've argued that one of the most important ideas of our time is connectionism, the doctrine that emphasizes the importance of connections for mental function. According to this notion, changing our brains is really about changing our connectomes. Connectionism dates back to the nineteenth century, but empirical evaluation of its claims has been difficult. At long last, thanks to the emerging technologies of connectomics, we are poised to test the doctrine. Is it indeed true that minds differ because connectomes differ? If we succeed in answering that question, we will also be able to identify desirable changes in the brain's wiring.

The next step will be to devise new methods of promoting such changes, based on molecular interventions that promote the four R's: reweighting, reconnection, rewiring, and regeneration. The methods would also utilize training regimens that harness the four R's to bring about positive changes.

To realize all these advances, we must continue to develop the necessary technologies. In the history of science, there are many examples of conceptual barriers that could not be surmounted by researchers, however brilliant they were, until the right tools became available. You wouldn't expect a caveman to figure out the workings of an old-fashioned mechanical clock if he didn't have a screwdriver. In the same vein, it's unrealistic to expect neuroscientists to figure out the brain without extremely sophisticated tools. Our technologies are starting to become equal to the task, but we will need to make them many times more powerful.

We need to create a research environment that fosters these technological advances. One possibility is to undertake “grand challenges,” ambitious projects that stimulate our imagination and mobilize our intellectual efforts. We could set a goal of finding the entire neuronal connectome of a mouse brain using electron microscopy, or the entire regional connectome of a human brain with light microscopy. The projects are of comparable difficulty, because they require the acquisition and analysis of similar amounts of data. I estimate that either would require a decade of intense effort. Both connectomes would be invaluable resources for neuroscientists, just as genomes have become indispensable to biologists.

These projects would be enormously difficult, but we could simultaneously pursue shortcuts. With the technologies developed, it would be possible to rapidly and cheaply find smaller connectomes. Compared with the grand challenges above, it should be a thousand times faster to find the neuronal connectome of a cubic millimeter of brain, or the regional connectome of a mouse brain. Finding many smaller connectomes would be important for studying individual differences and change.

Why should we invest in future technologies when we need to find better treatments for mental disorders right now? I think we should do both. Our therapies will surely improve over the next few years, but I expect that it will take decades to find true cures. Since this will be a continuing battle, it's worth making a reasonable investment today to reap rewards in the long run.

You may be skeptical that technology will ever progress enough to find connectomes quickly and cheaply. Before the Human Genome Project began, sequencing an entire human genome seemed almost impossible too. Connectomics might look difficult, but there's a certain sense in which it's trivial compared with the larger endeavor of neuroscience. Since the goal is well defined, we know exactly what success means, and can quantify progress. In contrast, the broader goal of neuroscience—to understand how the brain works—is only hazily defined. Even the experts don't agree about what it means. Once a goal is clearly defined, time, money, and effort are likely to yield progress. That's why I believe that connectomics will achieve its goals, however ambitious they might seem. We just need to rise to the challenge.

 

The young boy laughed as he splashed in the water. Returning to land, he asked, “Teacher, why does the stream flow?” The old man gazed silently at the novice and replied, “Earth tells water how to move.” During their journey back to the temple, they crossed a precarious footbridge. The novice clutched the old man's hand tightly. He looked at the stream far below and asked, “Teacher, why is the canyon so deep?” As they reached the safety of the other side, the old man replied, “Water tells earth how to move.”

I believe the stream inside our brain works in much the same way. The flow of neural activity through our connectomes drives our experiences of the present and leaves behind impressions that become our memories of the past. Connectomics marks a turning point in human history. As we evolved from apelike ancestors on the African savannah, what distinguished us was our larger brains. We have used our brains to fashion technologies that have given us ever more amazing capabilities. Eventually these technologies will become so powerful that we will use them to know ourselves—and to change ourselves for the better.

David van Essen planted the seed for this book by inviting me to lecture at the 2007 meeting of the Society for Neuroscience. Speaking before an audience of thousands, I concluded by laying out the challenge of finding connectomes. Upon hearing the buzz that followed, Bob Prior encouraged me to write a book. I took his suggestion but decided to target the general public. Since no knowledge could be assumed, I would have to argue from first principles and question all my beliefs. I was following the prescription “Empty your cup so that it may be filled.”

When I finished a draft in 2009, Catharine Carlin pointed me to Jim Levine, and Dan Ariely made the introduction. Jim's enthusiastic offer to serve as my agent was an enormous boost. He recruited the brilliant Amanda Cook, who has repeatedly prodded me with the question “Why should we care?” Beyond editing my writing and improving my storytelling, she has shaped my thinking. I never anticipated how drastically the book would change under her guidance, and I consider myself lucky that it did.

A life in science comes with a wonderful fringe benefit—opportunities to meet smart and interesting colleagues. Many fascinating discussions with other neuroscientists have enriched this book. The wise counsel of David Tank originally set me on the road to connectomes. The encouragement of Winfried Denk, who critiqued two drafts of the book, kept me writing. Jeff Lichtman patiently educated me about synapse elimination and neural Darwinism. Ken Hayworth explained his cutting machines and passionately argued the case for transhumanism. Daniel Berger contributed many suggestions for improving the book.