A WAY OUT?

The patternist has a response to all this, however. As noted, the reduplication problem suggests that sameness of pattern is not sufficient for sameness of person. You are more than just your pattern. But there still seems to be something right about patternism—for, as Kurzweil notes, throughout the course of your life, your cells change continually; it is your organizational pattern that carries on. Unless you have a religious conception of the person and adopt the soul theory, patternism may strike you as inevitable, at least insofar as you believe there is such a thing as a person to begin with.

In light of these observations, perhaps we should react to the reduplication case in the following way: Your pattern is essential to yourself despite not being sufficient for a complete account of your identity. Perhaps there is an additional essential property which, together with your pattern, yields a complete theory of personal identity.

What could the missing ingredient be? Intuitively, it must be a requirement that serves to rule out mindscans and, more generally, any cases in which the mind is uploaded. For any sort of uploading case will give rise to a reduplication problem, because uploaded minds can in principle be downloaded again and again.

Now think about your own existence in space and time. When you go out to get the mail, you move from one spatial location to the next, tracing a path in space. A spacetime diagram can help us visualize the path one takes throughout one’s life. Collapsing the three spatial dimensions into one (the vertical axis) and taking the horizontal axis to signify time, consider the following typical trajectory:

Notice that the figure carved out looks like a worm; you, like all physical objects, carve out a sort of “spacetime worm” over the course of your existence.

This, at least, is the kind of path that ordinary people—those who are neither posthumans nor superintelligences—carve out. But now consider what happened during the mindscan. Again, according to patternism, there would be two copies of the very same person. The copy’s spacetime diagram would look like the one pictured on the following page.

This is bizarre. It appears that Jake Sullivan exists for 42 years, has a scan, and then somehow instantaneously moves to a different location in space and lives out the rest of his life. This is radically unlike normal survival. This alerts us that something is wrong with pure patternism: It lacks a requirement for spatiotemporal continuity.

This additional requirement would seem to solve the reduplication problem. On the day of the mindscan, Jake went into the laboratory and had a scan; then he left the laboratory and went directly into a spaceship and flew to exile on the moon. It is this man—the one who traces a continuous trajectory through space and time—who is the true Jake Sullivan. The android is an unwitting impostor.

This response to the reduplication problem only goes so far, however. Consider Sugiyama, who, when selling his mindscan product, ventured a patternist pitch. If he had espoused patternism together with a spatiotemporal continuity clause, he would have to admit that his customers would not become immortal, and few would have signed up for the scan. That extra ingredient would rule out a mindscan (or any kind of uploading, for that matter) as a means to ensure survival. Only those wishing to have a replacement for themselves would sign up.

There is a general lesson here for the transhumanist or fusion-optimist: If one opts for patternism, enhancements like uploading to avoid death or to facilitate further enhancements are not really “enhancements;” they can even result in death. The fusion-optimist should sober up and not offer such procedures as enhancements. When it comes to enhancement, there are in principle limitations to what technology can deliver. Making copies of a mind does not count as an enhancement, because each individual mind still carries on, and it is subject to the limitations of its substrate. (Ironically, the proponent of the soul theory is in better shape here, because perhaps the soul does upload. If so, Jake could well wake up to find himself in the android body, while his original flesh is left a zombie, stripped of conscious experience. Who knows?)

Now let’s pause and take a breath. We’ve accomplished a lot in this chapter. We began by thinking about the Mindscan case, and a “reduplication problem” arose for patternism. This led us to discard the original form of patternism as false. I then suggested a way to modify patternism to arrive at a more realistic position. This meant adding a new element to the view—namely, the spatiotemporal continuity clause—which required that there be spatiotemporal continuity of a pattern for it to survive. I called this modified patternism. Modified patternism may strike you as more sensible, but notice that it doesn’t serve the fusion-optimist well, because it means that uploading is incompatible with survival, since uploading violates the spatiotemporal-continuity requirement.

But what about other AI-based enhancements? Are these ruled out as well? Consider, for instance, selecting a bundle of enhancements at the Center for Mind Design. These enhancements could dramatically alter your mental life, yet they do not involve uploading, and it is not obvious that spatiotemporal continuity would be violated.

Indeed, the fusion-optimist could point out that one could still merge with AI through a series of gradual but cumulatively significant enhancements that added AI-based components inside the head, slowly replacing neural tissue. This wouldn’t be uploading, because one’s thinking would still be inside the head, but the series still amounts to an attempt to transfer one’s mental life to another substrate. When the series was completed, if it worked, the individual’s mental life would have migrated from a biological substrate to a nonbiological one, such as silicon. And the fusion-optimist would be right: Humans can merge with AI.

Would it work? Here we need reconsider some issues raised in Chapter Five.

DEATH OR PERSONAL GROWTH?

Suppose you are at the Center for Mind Design, and you are gazing at the menu, considering buying a certain bundle of enhancements. Longing to upgrade yourself, you reluctantly consider whether modified patternism might be true. And you wonder: If I am a modified pattern, what happens to me when I add the enhancement bundle? My pattern will surely change, so would I die?

To determine whether this would be the case, the modified patternist would need to give a more precise account of what a “pattern” is and when different enhancements do and do not constitute a deadly break in the pattern. The extreme cases seem clear—for instance, as discussed, mindscans and duplication are ruled out by the spatiotemporal-continuity requirement. And, furthermore, because both versions of patternism are closely related to the older psychological-continuity approach, the modified patternist will likely want to say that a memory erasure process that erased several difficult years from one’s childhood is an unacceptable alteration of one’s pattern, removing too many of one’s memories and changing the person’s nature. In contrast, mere everyday cellular maintenance by nanobots swimming through your bloodstream to overcome the slow effects of aging would, presumably, not affect the identity of the person, for it wouldn’t alter one’s memories.

The problem is that the middle-range cases are unclear. Maybe deleting a few bad chess-playing habits is kosher, but what about more serious mindsculpting endeavors, like the enhancement bundle you were considering, or even adding a single cognitive capacity, for that matter? Or what about raising your IQ by 20 points or erasing all your memory of some personal relationship, as in the film Eternal Sunshine of the Spotless Mind? The path to superintelligence may very well be at the end of a gradual path through a series of these sorts of enhancements. But where do we draw the line?

Each of these enhancements is far less radical than uploading, but each one could be an alteration in the pattern that is incompatible with the preservation of the original person. And cumulatively, their impact on one’s pattern can be quite significant. So again, what is needed is a clear conception of what a pattern is, what changes in pattern are acceptable, and why. Without a firm handle on this issue, the transhumanist developmental trajectory is, for all we know, a technophile’s alluring path to suicide.

This problem looks hard to solve in a way that is compatible with preserving the very idea that we can be identical over time to some previous or future self. Determining a boundary point threatens to be an arbitrary exercise. Once a boundary is selected, an example can be provided, suggesting the boundary should be pushed outward, ad nauseam. But appreciate this point too long, and it may lead to a dark place: If one finds patternism or modified patternism compelling to begin with, how is it that one’s pattern truly persists over time, from the point of infancy until maturity, during which time there are often major changes in one’s memories, personality, and so on? Why is there a persisting self at all?

Indeed, even a series of gradual changes cumulatively amounts to an individual, B, who is greatly altered from her childhood self, A. Why is there really a relation of identity that holds between A and B, instead of an ancestral relation: A’s being the ancestor of B? Put differently, how can we tell if that future being who exists, after all these enhancements, is really us, and not, instead, a different person—a sort of “descendent” of ours?

It is worth pausing for a moment to reflect on the relationship between the ancestor and the descendant, although it is a bit of an aside. Suppose you are the ancestor. Your connection to your descendent resembles a parent-child relationship, but in some ways, it is more intimate, because you have first-person knowledge of the past of this new being. He or she is your mindchild. You have literally lived those past moments. In contrast, although we may feel closely connected to our children’s lives, we do not literally see the world through their eyes. In another sense, the relationship is weaker than many parent-child connections, however. Unless you are some sort of time traveler, the two of you will never even be in the same room. Like a woman who dies in childbirth, you will never meet the descendant who follows.

Perhaps your mindchild will come to mourn your passing, regarding you with deep affection and appreciating that the end of your life was the beginning of their own. For your part, you may feel a special connection to the range of experiences that will be enabled by the enhancements that you are about to purchase for your mindchild’s benefit. You may even feel a special connection to a being who you know will be nothing like you. For instance, in an act of benevolent mindsculpting, perhaps you would deliberately set out to create a superintelligent being, knowing that if you succeed, you will die.

In any case, the main point of this section has been to show you that even modified patternism faces a key challenge—it needs to tell us when a shift in one’s pattern is compatible with survival, and when it is not. Until it does, a cloud will hang over the fusion-optimist project. And this is not the only challenge for modified patternism.

DITCHING YOUR SUBSTRATE?

Modified patternism faces a second problem as well, one that challenges the very possibility that an individual could transfer to a different substrate, even with no cognitive or perceptual enhancements.

Suppose that it is 2050, and people are getting gradual neural regeneration procedures as they sleep. During their nightly slumbers, nanobots slowly import nanoscale materials that are computationally identical to the original materials. The nanobots then gradually remove the old materials, setting them in a small container beside the person’s bed.

By itself, this process is unproblematic for modified patternism. But now suppose there is an optional upgrade to the regeneration service for those who would like to make a backup copy of their brains. If one opts for this procedure, then during the nightly process, the nanobots take the replaced materials out of the dish and place them inside a cryogenically frozen biological brain. Suppose that by the end of the process, the materials in the frozen brain have been entirely replaced by the person’s original neurons, and they are configured the same way that they were in the original brain.

Now, suppose you choose to undergo this add-on procedure alongside your nightly regeneration. Over time, this second brain comes to be composed of the very same material as your brain originally was, configured in precisely the same manner. Which one is you? The original brain, which now has entirely different neurons, or the one with all your original neurons? The modified patternist has this to say about the neural regeneration case: You are the creature with the brain with entirely different matter, as this creature traces a continuous path through spacetime. But now, things go awry: Why is spatiotemporal continuity supposed to outweigh other factors, like being composed of the original material substrate?

Here, to be blunt, my intuitions crap out. I do not know whether this thought experiment is technologically feasible, but nevertheless, it raises an important conceptual flaw. We are trying to find out what the essential nature of a person is, so we’d like to find a solid justification for selecting one option over the other. Which is the deciding factor that is supposed to enable one to survive, in a case in which psychological continuity holds—being made of one’s original parts or preserving spatiotemporal continuity?

These problems suggest that modified patternism needs a good deal of spelling out. And remember, it wasn’t consistent with uploading in any case. The original patternist view held that one can survive uploading, but we discarded the view as deeply problematic. Until the fusion-optimist provides a solid justification for her position, it is best to view the idea of merging with AI with a good deal of skepticism. Indeed, after considering the vexing issue of persistence, perhaps we should even question the wisdom of a limited integration with AI, as middle-range enhancements are not clearly compatible with survival. Furthermore, even enhancements that merely involve the rapid or even gradual replacement of parts of one’s brain, without even enhancing one’s cognitive or perceptual skills, may be risky.

METAPHYSICAL HUMILITY

At the outset of the book, I asked you to imagine a shopping trip at the Center for Mind Design. You can now see how deceptively simple this thought experiment was. Perhaps the best response to the ongoing controversy over the nature of persons is to take a simple stance of metaphysical humility. Claims about survival that involve one “transferring” one’s mind to a new type of substrate or making drastic alterations to one’s brain should be carefully scrutinized. As alluring as greatly enhanced intelligence or digital immortality may be, we’ve seen that there is much disagreement in the personal-identity literature over whether any of these “enhancements” would extend life or terminate it.

A stance of metaphysical humility says that the way forward is public dialogue, informed by metaphysical theorizing. This may sound like a sort of intellectual copout, suggesting that scholars are of little use on this matter. But I am not suggesting that further metaphysical theorizing is useless; on the contrary, my hope is that this book illustrates the life-and-death import of further metaphysical reflection on these issues. The point is that ordinary individuals must be capable of making informed decisions about enhancement, and if the success of an enhancement rests on classic philosophical issues that are difficult to solve, the public needs to appreciate this problem. A pluralistic society should recognize the diversity of different views on these matters and not assume that science alone can answer questions about whether radical forms of brain enhancement are compatible with survival.

All this suggests that one should take the transhumanist approach to radical enhancement with a grain of salt. As “The Transhumanist Frequently Asked Questions” indicates, the development of enhancements like brain uploading or adding brain chips to augment intelligence or radically alter one’s perceptual abilities are key enhancements invoked by the transhumanist view of the development of the person.³ Such enhancements sound strangely like the thought experiments philosophers have used for years as problem cases for various theories of the nature of persons, so it shouldn’t surprise us one bit that the enhancements aren’t as attractive as they might seem at first.

We’ve learned that the Mindscan example suggests that one should not upload (at least not if one hopes to survive the process) and that the patternist needs to modify her theory to rule out such cases. Even with this modification in hand, however, transhumanism and fusion-optimism still require a detailed account of what constitutes a break in a pattern versus a mere continuation of it. Without progress on this issue, it will not be clear if medium-range enhancements, such as adding neural circuitry to make oneself smarter, are safe. Finally, the nanobot case warns against migrating to a different substrate, even if one’s mental abilities remain unchanged. Given all this, it is fair to say that the fusion-optimists or transhumanists have failed to support their case for enhancement. Indeed, “The Transhumanist Frequently Asked Questions” notes that transhumanists are keenly aware that this issue has been neglected:

While the concept of a soul is not used much in a naturalistic philosophy such as transhumanism, many transhumanists do take an interest in the related problems concerning personal identity (Parfit 1984) and consciousness (Churchland 1988). These problems are being intensely studied by contemporary analytic philosophers, and although some progress has been made, e.g. in Derek Parfit’s work on personal identity, they have still not been resolved to general satisfaction.⁴

Our discussion also raises general lessons for all parties involved in the enhancement debate, even where purely biological enhancements are concerned. When one considers the enhancement debate through the lens of the metaphysics of personhood, new dimensions of the debate unfurl. The literature on the nature of persons is extraordinarily rich, and when one defends or rejects a given enhancement, it is important to determine whether one’s stance on the enhancement in question is truly supported by (or even compatible with) leading views on the nature of persons.

Perhaps, alternately, you grow weary of all this metaphysics. You may suspect that we have to fall back on social conventions concerning what we commonly consider to be persons, because metaphysical theorizing will never conclusively resolve what persons are. However, not all conventions are worthy of acceptance, so one needs a manner of determining which conventions should play an important role in the enhancement debate and which ones should not. And it is hard to accomplish this without getting clear on one’s conception of persons. Furthermore, it is difficult to avoid at least implicitly relying on a conception of persons when reflecting on the case for and against enhancement. What is it that ultimately grounds your decision to enhance or not to enhance, if not that it will somehow improve you? Are you perhaps merely planning for the well-being of your successor?

We will return to personal identity in Chapter Eight. There, we will consider a related position on the fundamental nature of mind that says that the mind is software. But let’s pause for a moment. I’d like to raise the ante a bit. We’ve seen that each of us alive today may be one of the last biological rungs on the evolutionary ladder that leads from the first living cell to synthetic intelligence. On Earth, Homo sapiens may not be the most intelligent species for that much longer. In Chapter Seven, I’d like to explore the evolution of mind in a cosmic context. The minds on Earth—past, present, and future—may be but a small speck in the larger space of minds, a space that spans all of spacetime. As I write this, civilizations elsewhere in universe may be having their own singularities.