The Rational Argumentator

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By 2009 I felt the major classes of physicalist-functionalist replication approaches to be largely developed, producing now only potential minor variations in approach and procedure. These developments consisted of contingency plans in the case that some aspect of neuronal operation couldn’t be replicated with alternate, non-biological physical systems and processes, based around the goal of maintaining those biological (or otherwise organic) systems and processes artificially and of integrating them with the processes that could be reproduced artificially.

2009 also saw further developments in the computational approach, where I conceptualized a new sub-division in the larger class of the informational-functionalist (i.e., computational, which encompasses both simulation and emulation) replication approach, which is detailed in the next chapter.

Developments in the Physicalist Approach

During this time I explored mainly varieties of the cybernetic-physical functionalist approach. This involved the use of replicatory units that preserve certain biological aspects of the neuron while replacing certain others with functionalist replacements, and other NRUs that preserved alternate biological aspects of the neuron while replacing different aspects with functional replacements. The reasoning behind this approach was twofold. The first was that there was a chance, no matter how small, that we might fail to sufficiently replicate some relevant aspect(s) of the neuron either computationally or physically by failing to understand the underlying principles of that particular sub-process/aspect. The second was to have an approach that would work in the event that there was some material aspect that couldn’t be sufficiently replicated via non-biological physically embodied systems (i.e., the normative physical-functionalist approach).

However, these varieties were conceived of in case we couldn’t replicate certain components successfully (i.e., without functional divergence). The chances of preserving subjective-continuity in such circumstances are increased by the number of varieties we have for this class of model (i.e., different arrangements of mechanical replacement components and biological components), because we don’t know which we would fail to functionally replicate.

This class of physical-functionalist model can be usefully considered as electromechanical-biological hybrids, wherein the receptors (i.e., transporter proteins) on the post-synaptic membrane are integrated with the artificial membrane and in coexistence with artificial ion-channels, or wherein the biological membrane is retained while the receptor and ion-channels are replaced with functional equivalents instead. The biological components would be extracted from the existing biological neurons and reintegrated with the artificial membrane. Otherwise they would have to be synthesized via electromechanical systems, such as, but not limited to, the use of chemical stores of amino-acids released in specific sequences to facilitate in vivo protein folding and synthesis, which would then be transported to and integrated with the artificial membrane. This is better than providing stores of pre-synthesized proteins, due to more complexities in storing synthesized proteins without decay or functional degradation over storage-time, and in restoring them from their “stored”, inactive state to a functionally-active state when they were ready for use.

During this time I also explored the possibility of using the neuron’s existing protein-synthesis systems to facilitate the construction and gradual integration of the artificial sections with the existing lipid bilayer membrane. Work in synthetic biology allows us to use viral gene vectors to replace a given cell’s constituent genome—and consequently allowing us to make it manufacture various non-organic substances in replacement of the substances created via its normative protein-synthesis. We could use such techniques to replace the existing protein-synthesis instructions with ones that manufacture and integrate the molecular materials constituting the artificial membrane sections and artificial ion-channels and ion-pumps. Indeed, it may even be a functional necessity to gradually replace a given neuron’s protein-synthesis machinery with protein-synthesis-based machinery for the replacement, integration and maintenance of the non-biological sections’ material, because otherwise those parts of the neuron would still be trying to rebuild each section of lipid bilayer membrane we iteratively remove and replace. This could be problematic, and so for successful gradual replacement of single neurons, a means of gradually switching off and/or replacing portions of the cell’s protein-synthesis systems may be required.

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.