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Immortality: Bio or Techno? – Article by Franco Cortese

Immortality: Bio or Techno? – Article by Franco Cortese

The New Renaissance Hat
Franco Cortese
June 5, 2013
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This essay is the eleventh and final chapter in Franco Cortese’s forthcoming e-book, I Shall Not Go Quietly Into That Good Night!: My Quest to Cure Death, published by the Center for Transhumanity. The first ten chapters were previously published on The Rational Argumentator under the following titles:
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I Was a Techno-Immortalist Before I Came of Age

From the preceding chapters in this series, one can see that I recapitulated many notions and conclusions found in normative Whole-Brain Emulation. I realized that functional divergence between a candidate functional-equivalent and its original, through the process of virtual or artificial replication of environmental stimuli so as to coordinate their inputs, provides an experimental methodology for empirically validating the sufficiency and efficacy of different approaches. (Note, however, that such tests could not be performed to determine which NRU-designs or replication-approaches would preserve subjective-continuity, if the premises entertained during later periods of my project—that subjective-continuity may require a sufficient degree of operational “sameness”, and not just a sufficient degree of functional “sameness”—are correct.) I realized that we would only need to replicate in intensive detail and rigor those parts of our brain manifesting our personalities and higher cognitive faculties (i.e., the neocortex), and could get away with replicating at lower functional resolution the parts of the nervous system dealing with perception, actuation, and feedback between perception and actuation.

I read Eric Drexler’s Engines of Creation and imported the use of nanotechnology to facilitate both functional-replication (i.e., the technologies and techniques needed to replicate the functional and/or operational modalities of existing biological neurons) and the intensive, precise, and accurate scanning necessitated thereby. This was essentially Ray Kurzweil’s and Robert Freitas’s approach to the technological infrastructure needed for mind-uploading, as I discovered in 2010 via The Singularity is Near.

My project also bears stark similarities with Dmitry Itskov’s Project Avatar. My work on conceptual requirements for transplanting the biological brain into a fully cybernetic body — taking advantage of the technological and methodological infrastructures already in development for use in the separate disciplines of robotics, prosthetics, Brain-Computer Interfaces and sensory-substitution to facilitate the operations of the body — is a prefigurement of his Phase 1. My later work in approaches to functional replication of neurons for the purpose of gradual substrate replacement/transfer and integration also parallel his later phases, in which the brain is gradually replaced with an equivalent computational emulation.

The main difference between the extant Techno-Immortalist approaches, however, is my later inquiries into neglected potential bases for (a) our sense of experiential subjectivity (the feeling of being, what I’ve called immediate subjective-continuity)—and thus the entailed requirements for mental substrates aiming to maintain or attain such immediate subjectivity—and (b) our sense of temporal subjective-continuity (the feeling of being the same person through a process of gradual substrate-replacement—which I take pains to remind the reader already exists in the biological brain via the natural biological process of molecular turnover, which I called metabolic replacement throughout the course of the project), and, likewise, requirements for mental substrates aiming to maintain temporal subjective-continuity through a gradual substrate-replacement/transfer procedure.

In this final chapter, I summarize the main approaches to subjective-continuity thus far considered, including possible physical bases for its current existence and the entailed requirements for NRU designs (that is, for Techno-Immortalist approaches to indefinite-longevity) that maintain such physical bases of subjective-continuity. I will then explore why “Substrate-Independent Minds” is a useful and important term, and try to dispel one particularly common and easy-to-make misconception resulting from it.

Why Should We Worry about SubjectiveContinuity?

This concern marks perhaps the most telling difference between my project and normative Whole-Brain Emulation. Instead of stopping at the presumption that functional equivalence correlates with immediate subjective-continuity and temporal subjective-continuity, I explored several features of neural operation that looked like candidates for providing a basis of both types of subjective-continuity, by looking for those systemic properties and aspects that the biological brain possesses and other physical systems don’t. The physical system underlying the human mind (i.e., the brain) possesses experiential subjectivity; my premise was that we should look for properties not shared by other physical systems to find a possible basis for the property of immediate subjective-continuity. I’m not claiming that any of the aspects and properties considered definitely constitute such a basis; they were merely the avenues I explored throughout my 4-year quest to conquer involuntary death. I do claim, however, that we are forced to conclude that some aspect shared by the individual components (e.g., neurons) of the brain and not shared by other types of physical systems forms such a basis (which doesn’t preclude the possibility of immediate subjective-continuity being a spectrum or gradient rather than a definitive “thing” or process with non-variable parameters), or else that immediate subjective continuity is a normal property of all physical systems, from atoms to rocks.

A phenomenological proof of the non-equivalence of function and subjectivity or subjective-experientiality is the physical irreducibility of qualia – that we could understand in intricate detail the underlying physics of the brain and sense-organs, and nowhere derive or infer the nature of the qualia such underlying physics embodies. To experimentally verify which approaches to replication preserve both functionality and subjectivity would necessitate a science of qualia. This could be conceivably attempted through making measured changes to the operation or inter-component relations of a subject’s mind (or sense organs)—or by integrating new sense organs or neural networks—and recording the resultant changes to his experientiality—that is, to what exactly he feels. Though such recordings would be limited to his descriptive ability, we might be able to make some progress—e.g., he could detect the generation of a new color, and communicate that it is indeed a color that doesn’t match the ones normally available to him, while still failing to communicate to others what the color is like experientially or phenomenologically (i.e., what it is like in terms of qualia). This gets cruder the deeper we delve, however. While we have unchanging names for some “quales” (i.e., green, sweetness, hot, and cold), when it gets into the qualia corresponding with our perception of our own “thoughts” (which will designate all non-normatively perceptual experiential modalities available to the mind—thus, this would include wordless “daydreaming” and exclude autonomic functions like digestion or respiration), we have both far less precision (i.e., fewer words to describe) and less accuracy (i.e., too many words for one thing, which the subject may confuse; the lack of a quantitative definition for words relating to emotions and mental modalities/faculties seems to ensure that errors may be carried forward and increase with each iteration, making precise correlation of operational/structural changes with changes to qualia or experientiality increasingly harder and more unlikely).

Thus whereas the normative movements of Whole-Brain Emulation and Substrate-Independent Minds stopped at functional replication, I explored approaches to functional replication that preserved experientiality (i.e., a subjective sense of anything) and that maintained subjective-continuity (the experiential correlate of feeling like being yourself) through the process of gradual substrate-transfer.

I do not mean to undermine in any way Whole-Brain Emulation and the movement towards Substrate-Independent Minds promoted by such people as Randal Koene via, formerly, his minduploading.org website and, more recently, his Carbon Copies project, Anders Sandberg and Nick Bostrom through their WBE Roadmap, and various other projects on connectomes. These projects are untellably important, but conceptions of subjective-continuity (not pertaining to its relation to functional equivalence) are beyond their scope.

Whether or not subjective-continuity is possible through a gradual-substrate-replacement/transfer procedure is not under question. That we achieve and maintain subjective-continuity despite our constituent molecules being replaced within a period of 7 years, through what I’ve called “metabolic replacement” but what would more normatively be called “molecular-turnover” in molecular biology, is not under question either. What is under question is (a) what properties biological nervous systems possess that could both provide a potential physical basis for subjective-continuity and that other physical systems do not possess, and (b) what the design requirements are for approaches to gradual substrate replacement/transfer that preserve such postulated sources of subjective-continuity.

Graduality

This was the first postulated basis for preserving temporal subjective-continuity. Our bodily systems’ constituent molecules are all replaced within a span of 7 years, which provides empirical verification for the existence of temporal subjective-continuity through gradual substrate replacement. This is not, however, an actual physical basis for immediate subjective-continuity, like the later avenues of enquiry. It is rather a way to avoid causing externally induced subjective-discontinuity, rather than maintaining the existing biological bases for subjective-discontinuity. We are most likely to avoid negating subjective-continuity through a substrate-replacement procedure if we try to maintain the existing degree of graduality (the molecular-turnover or “metabolic-replacement” rate) that exists in biological neurons.

The reasoning behind concerns of graduality also serves to illustrate a common misconception created by the term “Substrate-Independent Minds”. This term should denote the premise that mind can be instantiated on different types of substrate, in the way that a given computer program can run of different types of computational hardware. It stems from the scientific-materialist (a.k.a metaphysical-naturalist) claim that mind is an emergent process not reducible to its isolated material constituents, while still being instantiated thereby. The first (legitimate) interpretation is a refutation against all claims of metaphysical vitalism or substance dualism. The term should not denote the claim that since mind because is software, we can thus send our minds (say, encoded in a wireless signal) from one substrate to another without subjective-discontinuity. This second meaning would incur the emergent effect of a non-gradual substrate-replacement procedure (that is, the wholesale reconstruction of a duplicate mind without any gradual integration procedure). In such a case one stops all causal interaction between components of the brain—in effect putting it on pause. The brain is now static. This is even different than being in an inoperative state, where at least the components (i.e., neurons) still undergo minor operational fluctuations and are still “on” in an important sense (see “Immediate Subjective-Continuity” below), which is not the case here. Beaming between substrates necessitates that all causal interaction—and thus procedural continuity—between software-components is halted during the interval of time in which the information is encoded, sent wirelessly, and subsequently decoded. It would be reinstantiated upon arrival in the new substrate, yes, but not without being put on pause in the interim. The phrase “Substrate-Independent Minds” is an important and valuable one and should be indeed be championed with righteous vehemence—but only in regard to its first meaning (that mind can be instantiated on various different substrates) and not its second, illegitimate meaning (that we ourselves can switch between mental substrates, without any sort of gradual-integration procedure, and still retain subjective-continuity).

Later lines of thought in this regard consisted of positing several sources of subjective-continuity and then conceptualizing various different approaches or varieties of NRU-design that would maintain these aspects through the gradual-replacement procedure.

Immediate Subjective-Continuity

This line of thought explored whether certain physical properties of biological neurons provide the basis for subjective-continuity, and whether current computational paradigms would need to possess such properties in order to serve as a viable substrate-for-mind—that is, one that maintains subjective-continuity. The biological brain has massive parallelism—that is, separate components are instantiated concurrently in time and space. They actually exist and operate at the same time. By contrast, current paradigms of computation, with a few exceptions, are predominantly serial. They instantiate a given component or process one at a time and jump between components or processes so as to integrate these separate instances and create the illusion of continuity. If such computational paradigms were used to emulate the mind, then only one component (e.g., neuron or ion-channel, depending on the chosen model-scale) would be instantiated at a given time. This line of thought postulates that computers emulating the mind may need to be massively parallel in the same way that as the biological brain is in order to preserve immediate subjective-continuity.

Procedural Continuity

Much like the preceding line of thought, this postulates that a possible basis for temporal subjective-continuity is the resting membrane potential of neurons. While in an inoperative state—i.e., not being impinged by incoming action-potentials, or not being stimulated—it (a) isn’t definitively off, but rather produces a baseline voltage that assures that there is no break (or region of discontinuity) in its operation, and (b) still undergoes minor fluctuations from the baseline value within a small deviation-range, thus showing that causal interaction amongst the components emergently instantiating that resting membrane potential (namely ion-pumps) never halts. Logic gates on the other hand do not produce a continuous voltage when in an inoperative state. This line of thought claims that computational elements used to emulate the mind should exhibit the generation of such a continuous inoperative-state signal (e.g., voltage) in order to maintain subjective-continuity. The claim’s stronger version holds that the continuous inoperative-state signal produced by such computational elements undergo minor fluctuations (i.e., state-transitions) allowed within the range of the larger inoperative-state signal, which maintains causal interaction among lower-level components and thus exhibits the postulated basis for subjective-continuity—namely procedural continuity.

Operational Isomorphism

This line of thought claims that a possible source for subjective-continuity is the baseline components comprising the emergent system instantiating mind. In physicality this isn’t a problem because the higher-scale components (e.g., single neurons, sub-neuron components like ion-channels and ion-pumps, and individual protein complexes forming the sub-components of an ion-channel or pump) are instantiated by the lower-level components. Those lower-level components are more similar in terms of the rules determining behavior and state-changes. At the molecular scale, the features determining state-changes (intra-molecular forces, atomic valences, etc.) are the same. This changes as we go up the scale—most notably at the scale of high-level neural regions/systems. In a software model, however, we have a choice as to what scale we use as our model-scale. This postulated source of subjective-continuity would entail that we choose as our model-scale one in which the components of that scale have a high degree of this property (operational isomorphism—or similarity) and that we not choosing a scale at which the components have a lesser degree of this property.

Operational Continuity

This line of thought explored the possibility that we might introduce operational discontinuity by modeling (i.e., computationally instantiating) not the software instantiated by the physical components of the neuron, but instead those physical components themselves—which for illustrative purposes can be considered as the difference between instantiating software and instantiating physics of the logic gates giving rise to the software. Though the software would necessarily be instantiated as a vicarious result of computationally instantiating its biophysical foundation rather than the software directly, we may be introducing additional operational steps and thus adding an unnecessary dimension of discontinuity that needlessly jeopardizes the likelihood of subjective-continuity.

These concerns are wholly divorced from functionalist concerns. If we disregarded these potential sources of subjective-continuity, we could still functionally-replicate a mind in all empirically-verifiable measures yet nonetheless fail to create minds possessing experiential subjectivity. Moreover, the verification experiments discussed in Part 2 do provide a falsifiable methodology for determining which approaches best satisfy the requirements of functional equivalence. They do not, however, provide a method of determining which postulated sources of subjective-continuity are true—simply because we have no falsifiable measures to determine either immediate or temporal subjective-discontinuity, other than functionality. If functional equivalence failed, it would tell us that subjective-continuity failed to be maintained. If functional-equivalence was achieved, however, it doesn’t necessitate that subjective-continuity was maintained.

Bio or Cyber? Does It Matter?

Biological approaches to indefinite-longevity, such as Aubrey de Grey’s SENS and Michael Rose’s Evolutionary Selection for Longevity, among others, have both comparative advantages and drawbacks. The chances of introducing subjective-discontinuity are virtually nonexistent compared to non-biological (which I will refer to as Techno-Immortalist) approaches. This makes them at once more appealing. However, it remains to be seen whether the advantages of the techno-immortalist approach supersede their comparative dangers in regard to their potential to introduce subjective-discontinuity. If such dangers can be obviated, however, it has certain potentials which Bio-Immortalist projects lack—or which are at least comparatively harder to facilitate using biological approaches.

Perhaps foremost among these potentials is the ability to actively modulate and modify the operations of individual neurons, which, if integrated across scales (that is, the concerted modulation/modification of whole emergent neural networks and regions via operational control over their constituent individual neurons), would allow us to take control over our own experiential and functional modalities (i.e., our mental modes of experience and general abilities/skills), thus increasing our degree of self-determination and the control we exert over the circumstances and determining conditions of our own being. Self-determination is the sole central and incessant essence of man; it is his means of self-overcoming—of self-dissent in a striving towards self-realization—and the ability to increase the extent of such self-control, self-mastery, and self-actualization is indeed a comparative advantage of techno-immortalist approaches.

To modulate and modify biological neurons, on the other hand, necessitates either high-precision genetic engineering, or likely the use of nanotech (i.e., NEMS), because whereas the proposed NRUs already have the ability to controllably vary their operations, biological neurons necessitate an external technological infrastructure for facilitating such active modulation and modification.

Biological approaches to increased longevity also appear to necessitate less technological infrastructure in terms of basic functionality. Techno-immortalist approaches require precise scanning technologies and techniques that neither damage nor distort (i.e., affect to the point of operational and/or functional divergence from their normal in situ state of affairs) the features and properties they are measuring. However, there is a useful distinction to be made between biological approaches to increased longevity, and biological approaches to indefinite longevity. Aubrey de Grey’s notion of Longevity Escape Velocity (LEV) serves to illustrate this distinction. With SENS and most biological approaches, he points out that although remediating certain biological causes of aging will extend our lives, by that time different causes of aging that were superseded (i.e., prevented from making a significant impact on aging) by the higher-impact causes of aging may begin to make a non-negligible impact. Aubrey’s proposed solution is LEV: if we can develop remedies for these approaches within the amount of time gained by the remediation of the first set of causes, then we can stay on the leading edge and continue to prolong our lives. This is in contrast to other biological approaches, like Eric Drexler’s conception of nanotechnological cell-maintenance and cell-repair systems, which by virtue of being able to fix any source of molecular damage or disarray vicariously, not via eliminating the source but via iterative repair and/or replacement of the causes or “symptoms” of the source, will continue to work on any new molecular causes of damage without any new upgrades or innovations to their underlying technological and methodological infrastructures.

These would be more appropriately deemed an indefinite-biological-longevity technology, in contrast to biological-longevity technologies. Techno-immortalist approaches are by and large exclusively of the indefinite-longevity-extension variety, and so have an advantage over certain biological approaches to increased longevity, but such advantages do not apply to biological approaches to indefinite longevity.

A final advantage of techno-immortalist approaches is the independence of external environments it provides us. It also makes death by accident far less likely both by enabling us to have more durable bodies and by providing independence from external environments, which means that certain extremes of temperature, pressure, impact-velocity, atmosphere, etc., will not immediately entail our death.

I do not want to discredit any approaches to immortality discussed in this essay, nor any I haven’t mentioned. Every striving and attempt at immortality is virtuous and righteous, and this sentiment will only become more and apparent, culminating on the day when humanity looks back, and wonders how we could have spent so very much money and effort on the Space Race to the Moon with no perceivable scientific, resource, or monetary gain (though there were some nationalistic and militaristic considerations in terms of America not being superseded on either account by Russia), yet took so long to make a concerted global effort to first demand and then implement well-funded attempts to finally defeat death—that inchoate progenitor of 100,000 unprecedented cataclysms a day. It’s true—the world ends 100,000 times a day, to be lighted upon not once more for all of eternity. Every day. What have you done to stop it?

So What?

Indeed, so what? What does this all mean? After all, I never actually built any systems, or did any physical experimentation. I did, however, do a significant amount of conceptual development and thinking on both the practical consequences (i.e., required technologies and techniques, different implementations contingent upon different premises and possibilities, etc.) and the larger social and philosophical repercussions of immortality prior to finding out about other approaches. And I planned on doing physical experimentation and building physical systems; but I thought that working on it in my youth, until such a time as to be in the position to test and implement these ideas more formally via academia or private industry, would be better for the long-term success of the endeavor.

As noted in Chapter 1, this reifies the naturality and intuitive simplicity of indefinite longevity’s ardent desirability and fervent feasibility, along a large variety of approaches ranging from biotechnology to nanotechnology to computational emulation. It also reifies the naturality and desirability of Transhumanism. I saw one of the virtues of this vision as its potential to make us freer, to increase our degree of self-determination, as giving us the ability to look and feel however we want, and the ability to be—and more importantly to become—anything we so desire. Man is marked most starkly by his urge and effort to make his own self—to formulate the best version of himself he can, and then to actualize it. We are always reaching toward our better selves—striving forward in a fit of unbound becoming toward our newest and thus truest selves; we always have been, and with any courage we always will.

Transhumanism is but the modern embodiment of our ancient striving towards increased self-determination and self-realization—of all we’ve ever been and done. It is the current best contemporary exemplification of what has always been the very best in us—the improvement of self and world. Indeed, the ‘trans’ and the ‘human’ in Transhumanism can only signify each other, for to be human is to strive to become more than human—or to become more so human, depending on which perspective you take.

So come along and long for more with me; the best is e’er yet to be!

Franco Cortese is an editor for Transhumanity.net, as well as one of its most frequent contributors.  He has also published articles and essays on Immortal Life and The Rational Argumentator. He contributed 4 essays and 7 debate responses to the digital anthology Human Destiny is to Eliminate Death: Essays, Rants and Arguments About Immortality.

Franco is an Advisor for Lifeboat Foundation (on its Futurists Board and its Life Extension Board) and contributes regularly to its blog.

Bibliography

Koene, R. (2011). What is carboncopies.org? Retrieved February 28, 2013 from http://www.carboncopies.org/

Rose, M. (October 28 2004). Biological Immortality. In B. Klein, The Scientific Conquest of Death (pp. 17-28). Immortality Institute.

Sandberg, A., & Bostrom, N. (2008). Whole Brain Emulation: A Roadmap, Technical Report #2008-3. Retrieved February 28, 2013 http://www.philosophy.ox.ac.uk/__data/assets/pdf_file/0019/3853/brain-emulation-roadmap-report.pdf

Sandberg, A., & Bostrom, Koene, R. (2011). The Society of Neural Prosthetics and Whole Brain Emulation Science. Retrieved February 28, 2013 from http://www.minduploading.org/

de Grey, ADNJ (2004). Escape Velocity: Why the Prospect of Extreme Human Life Extension Matters Now. PLoS Biol 2(6): e187. doi:10.1371/journal.pbio.0020187

Wireless Synapses, Artificial Plasticity, and Neuromodulation – Article by Franco Cortese

Wireless Synapses, Artificial Plasticity, and Neuromodulation – Article by Franco Cortese

The New Renaissance Hat
Franco Cortese
May 21, 2013
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This essay is the fifth chapter in Franco Cortese’s forthcoming e-book, I Shall Not Go Quietly Into That Good Night!: My Quest to Cure Death, published by the Center for Transhumanity. The first four chapters were previously published on The Rational Argumentator as “The Moral Imperative and Technical Feasibility of Defeating Death”, “Immortality: Material or Ethereal? Nanotech Does Both!, “Concepts for Functional Replication of Biological Neurons“, and “Gradual Neuron Replacement for the Preservation of Subjective-Continuity“.
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Morphological Changes for Neural Plasticity

The finished physical-functionalist units would need the ability to change their emergent morphology not only for active modification of single-neuron functionality but even for basic functional replication of normative neuron behavior, by virtue of needing to take into account neural plasticity and the way that morphological changes facilitate learning and memory. My original approach involved the use of retractable, telescopic dendrites and axons (with corresponding internal retractable and telescopic dendritic spines and axonal spines, respectively) activated electromechanically by the unit-CPU. For morphological changes, by providing the edges of each membrane section with an electromechanical hinged connection (i.e., a means of changing the angle of inclination between immediately adjacent sections), the emergent morphology can be controllably varied. This eventually developed to consist of an internal compartment designed so as to detach a given membrane section, move it down into the internal compartment of the neuronal soma or terminal, transport it along a track that stores alternative membrane sections stacked face-to-face (to compensate for limited space), and subsequently replaces it with a membrane section containing an alternate functional component (e.g., ion pump, ion channel, [voltage-gated or ligand-gated], etc.) embedded therein. Note that this approach was also conceived of as an alternative to retractable axons/dendrites and axonal/dendritic spines, by attaching additional membrane sections with a very steep angle of inclination (or a lesser inclination with a greater quantity of segments) and thereby creating an emergent section of artificial membrane that extends out from the biological membrane in the same way as axons and dendrites.

However, this approach was eventually supplemented by one that necessitates less technological infrastructure (i.e., that was simpler and thus more economical and realizable). If the size of the integral-membrane components is small enough (preferably smaller than their biological analogues), then differential activation of components or membrane sections would achieve the same effect as changing the organization or type of integral-membrane components, effectively eliminating the need at actually interchange membrane sections at all.

Active Neuronal Modulation and Modification

The technological and methodological infrastructure used to facilitate neural plasticity can also be used for active modification and modulation of neural behavior (and the emergent functionality determined by local neuronal behavior) towards the aim of mental augmentation and modification. Potential uses already discussed include mental amplification (increasing or augmenting existing functional modalities—i.e., intelligence, emotion, morality), or mental augmentation (the creation of categorically new functional and experiential modalities). While the distinction between modification and modulation isn’t definitive, a useful way of differentiating them is to consider modification as morphological changes creating new functional modalities, and to consider modulation as actively varying the operation of existing structures/processes through not morphological change but rather changes to the operation of integral-membrane components or the properties of the local environment (e.g., increasing local ionic concentrations).

Modulation: A Less Discontinuous Alternative to Morphological Modification

The use of modulation to achieve the effective results of morphological changes seemed like a hypothetically less discontinuous alternative to morphological changes (and thus as having a hypothetically greater probability of achieving subjective-continuity). I’m more dubious in regards to the validity of this approach now, because the emergent functionality (normatively determined by morphological features) is still changed in an effectively equivalent manner.

The Eventual Replacement of Neural Ionic Solutions with Direct Electric Fields

Upon full gradual replacement of the CNS with physical-functionalist equivalents, the preferred embodiment consisted of replacing the ionic solutions with electric fields that preserve the electric potential instantiated by the difference in ionic concentrations on the respective sides of the membrane. Such electric fields can be generated directly, without recourse to electrochemicals for manifesting them. In such a case the integral-membrane components would be replaced by a means of generating and maintaining a static and/or dynamic electric field on either side of the membrane, or even merely of generating an electrical potential (i.e., voltage—a broader category encompassing electric fields) with solid-state electronics.

This procedure would allow a fraction of the speedups (that is, increased rate of subjective perception of time, which extends to speed of thought) resulting from emulatory (i.e., strictly computational) replication-methods by no longer being limited to the rate of passive ionic diffusion—now instead being limited to the propagation velocity of electric or electromagnetic fields.

Wireless Synapses

If we replace the physical synaptic connections the NRU uses to communicate (with both existing biological neurons and with other NRUs) with a wireless means of synaptic-transmission, we can preserve the same functionality (insofar as it is determined by synaptic connectivity) while allowing any NRU to communicate with any other NRU or biological neuron in the brain at potentially equal speed. First we need a way of converting the output of an NRU or biological neuron into information that can be transmitted wirelessly. For cyber-physicalist-functionalist NRUs, regardless of their sub-class, this requires no new technological infrastructure because they already deal with 2nd-order (i.e., not structurally or directly embodied) information; informational-functional NRU deals solely in terms of this type of information, and the cyber-physical-systems sub-class of the physicalist-functionalist NRUs deal with this kind of information in the intermediary stage between sensors and actuators—and consequently, converting what would have been a sequence of electromechanical actuations into information isn’t a problem. Only the passive-physicalist-functionalist NRU class requires additional technological infrastructure to accomplish this, because they don’t already use computational operational-modalities for their normative operation, whereas the other NRU classes do.

We dispose receivers within the range of every neuron (or alternatively NRU) in the brain, connected to actuators – the precise composition of which depends on the operational modality of the receiving biological neuron or NRU. The receiver translates incoming information into physical actuations (e.g., the release of chemical stores), thereby instantiating that informational output in physical terms. For biological neurons, the receiver’s actuators would consist of a means of electrically stimulating the neuron and releasable chemical stores of neurotransmitters (or ionic concentrations as an alternate means of electrical stimulation via the manipulation of local ionic concentrations). For informational-functionalist NRUs, the information is already in a form it can accept; it can simply integrate that information into its extant model. For cyber-physicalist-NRUs, the unit’s CPU merely needs to be able to translate that information into the sequence in which it must electromechanically actuate its artificial ion-channels. For the passive-physicalist (i.e., having no computational hardware devoted to operating individual components at all, operating according to physical feedback between components alone) NRUs, our only option appears to be translating received information into the manipulation of the local environment to vicariously affect the operation of the NRU (e.g., increasing electric potential through manipulations of local ionic concentrations, or increasing the rate of diffusion via applied electric fields to attract ions and thus achieve the same effect as a steeper electrochemical gradient or potential-difference).

The technological and methodological infrastructure for this is very similar to that used for the “integrational NRUs”, which allows a given NRU-class to communicate with either existing biological neurons or NRUs of an alternate class.

Integrating New Neural Nets Without Functional Distortion of Existing Regions

The use of artificial neural networks (which here will designate NRU-networks that do not replicate any existing biological neurons, rather than the normative Artificial Neuron Networks mentioned in the first and second parts of this essay), rather than normative neural prosthetics and BCI, was the preferred method of cognitive augmentation (creation of categorically new functional/experiential modalities) and cognitive amplification (the extension of existing functional/experiential modalities). Due to functioning according to the same operational modality as existing neurons (whether biological or artificial-replacements), they can become a continuous part of our “selves”, whereas normative neural prosthetics and BCI are comparatively less likely to be capable of becoming an integral part of our experiential continuum (or subjective sense of self) due to their significant operational dissimilarity in relation to biological neural networks.

A given artificial neural network can be integrated with existing biological networks in a few ways. One is interior integration, wherein the new neural network is integrated so as to be “inter-threaded”, in which a given artificial-neuron is placed among one or multiple existing networks. The networks are integrated and connected on a very local level. In “anterior” integration, the new network would be integrated in a way comparable to the connection between separate cortical columns, with the majority of integration happening at the peripherals of each respective network or cluster.

If the interior integration approach is used then the functionality of the region may be distorted or negated by virtue of the fact that neurons that once took a certain amount of time to communicate now take comparatively longer due to the distance between them having been increased to compensate for the extra space necessitated by the integration of the new artificial neurons. Thus in order to negate these problematizing aspects, a means of increasing the speed of communication (determined by both [a] the rate of diffusion across the synaptic junction and [b] the rate of diffusion across the neuronal membrane, which in most cases is synonymous with the propagation velocity in the membrane – the exception being myelinated axons, wherein a given action potential “jumps” from node of Ranvier to node of Ranvier; in these cases propagation velocity is determined by the thickness and length of the myelinated sections) must be employed.

My original solution was the use of an artificial membrane morphologically modeled on a myelinated axon that possesses very high capacitance (and thus high propagation velocity), combined with increasing the capacitance of the existing axon or dendrite of the biological neuron. The cumulative capacitance of both is increased in proportion to how far apart they are moved. In this way, the propagation velocity of the existing neuron and the connector-terminal are increased to allow the existing biological neurons to communicate as fast as they would have prior to the addition of the artificial neural network. This solution was eventually supplemented by the wireless means of synaptic transmission described above, which allows any neuron to communicate with any other neuron at equal speed.

Gradually Assigning Operational Control of a Physical NRU to a Virtual NRU

This approach allows us to apply the single-neuron gradual replacement facilitated by the physical-functionalist NRU to the informational-functionalist (physically embodied) NRU. A given section of artificial membrane and its integral membrane components are modeled. When this model is functioning in parallel (i.e., synchronization of operative states) with its corresponding membrane section, the normative operational routines of that artificial membrane section (usually controlled by the unit’s CPU and its programming) are subsequently taken over by the computational model—i.e., the physical operation of the artificial membrane section is implemented according to and in correspondence with the operative states of the model. This is done iteratively, with the informationalist-functionalist NRU progressively controlling more and more sections of the membrane until the physical operation of the whole physical-functionalist NRU is controlled by the informational operative states of the informationalist-functionalist NRU. While this concept sprang originally from the approach of using multiple gradual-replacement phases (with a class of model assigned to each phase, wherein each is more dissimilar to the original than the preceding phase, thereby increasing the cumulative degree of graduality), I now see it as a way of facilitating sub-neuron gradual replacement in computational NRUs. Also note that this approach can be used to go from existing biological membrane-sections to a computational NRU, without a physical-functionalist intermediary stage. This, however, is comparatively more complex because the physical-functionalist NRU already has a means of modulating its operative states, whereas the biological neuron does not. In such a case the section of lipid bilayer membrane would presumably have to be operationally isolated from adjacent sections of membrane, using a system of chemical inventories (of either highly concentrated ionic solution or neurotransmitters, depending on the area of membrane) to produce electrochemical output and chemical sensors to accept the electrochemical input from adjacent sections (i.e., a means of detecting depolarization and hyperpolarization). Thus to facilitate an action potential, for example, the chemical sensors would detect depolarization, the computational NRU would then model the influx of ions through the section of membrane it is replacing and subsequently translate the effective results impinging upon the opposite side to that opposite edge via either the release of neurotransmitters or the manipulation of local ionic concentrations so as to generate the required depolarization at the adjacent section of biological membrane.

Integrational NRU

This consisted of a unit facilitating connection between emulatory (i.e., informational-functionalist) units and existing biological neurons. The output of the emulatory units is converted into chemical and electrical output at the locations where the emulatory NRU makes synaptic connection with other biological neurons, facilitated through electric stimulation or the release of chemical inventories for the increase of ionic concentrations and the release of neurotransmitters, respectively. The input of existing biological neurons making synaptic connections with the emulatory NRU is read, likewise, by chemical and electrical sensors and is converted into informational input that corresponds to the operational modality of the informationalist-functionalist NRU classes.

Solutions to Scale

If we needed NEMS or something below the scale of the present state of MEMS for the technological infrastructure of either (a) the electromechanical systems replicating a given section of neuronal membrane, or (b) the systems used to construct and/or integrate the sections, or those used to remove or otherwise operationally isolate the existing section of lipid bilayer membrane being replaced from adjacent sections, a postulated solution consisted of taking the difference in length between the artificial membrane section and the existing bilipid section (which difference is determined by how small we can construct functionally operative artificial ion-channels) and incorporating this as added curvature in the artificial membrane-section such that its edges converge upon or superpose with the edges of the space left by the removal the lipid bilayer membrane-section. We would also need to increase the propagation velocity (typically determined by the rate of ionic influx, which in turn is typically determined by the concentration gradient or difference in the ionic concentrations on the respective sides of the membrane) such that the action potential reaches the opposite end of the replacement section at the same time that it would normally have via the lipid bilayer membrane. This could be accomplished directly by the application of electric fields with a charge opposite that of the ions (which would attract them, thus increasing the rate of diffusion), by increasing the number of open channels or the diameter of existing channels, or simply by increasing the concentration gradient through local manipulation of extracellular and/or intracellular ionic concentration—e.g., through concentrated electrolyte stores of the relevant ion that can be released to increase the local ionic concentration.

If the degree of miniaturization is so low as to make this approach untenable (e.g., increasing curvature still doesn’t allow successful integration) then a hypothesized alternative approach was to increase the overall space between adjacent neurons, integrate the NRU, and replace normative connection with chemical inventories (of either ionic compound or neurotransmitter) released at the site of existing connection, and having the NRU (or NRU sub-section—i.e., artificial membrane section) wirelessly control the release of such chemical inventories according to its operative states.

The next chapter describes (a) possible physical bases for subjective-continuity through a gradual-uploading procedure and (b) possible design requirements for in vivo brain-scanning and for systems to construct and integrate the prosthetic neurons with the existing biological brain.

Franco Cortese is an editor for Transhumanity.net, as well as one of its most frequent contributors.  He has also published articles and essays on Immortal Life and The Rational Argumentator. He contributed 4 essays and 7 debate responses to the digital anthology Human Destiny is to Eliminate Death: Essays, Rants and Arguments About Immortality.

Franco is an Advisor for Lifeboat Foundation (on its Futurists Board and its Life Extension Board) and contributes regularly to its blog.

Bibliography

Project Avatar (2011). Retrieved February 28, 2013 from http://2045.com/tech2/