Mind uploading advocate Kenneth Hayworth has launched an interesting website devoted to the science of brain preservation. Of particular interest is his Proposal for a Brain Preservation Technology Prize (PDF). This document includes one of the most comprehensive discussions of chemopreservation as a strategy for personal survival. For example, one of the most common objections to chemopreservation is that fixatives like formaldehyde and glutaraldehyde do a poor job of fixing lipids. In this document, Hayworth reviews a number of papers where a fixative that can stabilize lipids, osmium tetroxide, is perfused (!) through the circulatory system. For human sized brains such a step would be necessary to avoid the ischemic damage and autolysis that would occur in the case of the time-consuming alternative of diffusion fixation. He also speculates that such a fixed brain can be perfused with a high viscosity plastic resin for long term preservation.
One of the limitations of this approach, as the author concedes, is that the procedure needs to be started before death. In reality, the situation is even more challenging than that because the procedure would have to be started before ischemia-induced brain perfusion abnormalities associated with terminal disease and the agonal phase will manifest themselves. This is a problem where “old fashioned” cryonics has a clear advantage. Perfusion impairment may interfere with complete distribution and equilibration of the cryoprotectant in the brain but the unperfused tissues will still be stabilized (although in a damaged form) through low temperatures. In the case of chemical fixation such a “second chance” is absent. This is not just a theoretical problem. Cryonics researchers have become painfully aware of the adverse effects of even the slightest perfusion artifacts on the quality of fixation and the resulting electron micrographs.
As a consequence, this kind of “high quality” chemopreservation can only be a credible alternative for cryonics if the medical establishment would permit the procedure for those who are diagnosed as terminally ill. If the acceptance of cryonics is any guidance, there is little chance that this will happen any time soon.
Chemopreservation has another major obstacle to deal with. As the cryobiologist Brain Wowk has stated on numerous occasions, chemical fixation is a dead end in terms of reversibility with contemporary technologies. This aspect of chemical fixation limits the demonstration of its technical feasibility to a demonstration of ultrastructural preservation. In the case of cryonics, evidence of excellent ultrastructural preservation has produced little excitement among the scientific establishment and the general public. Linking chemopreservation exclusively to mind uploading may present another obstacle to its acceptance.
In his essay Killed by Bad Philosophy: Why brain preservation followed by mind uploading is a cure for death [PDF] Kenneth Hayworth attempts a defense of mind uploading by identifying the philosophical errors that those who reject the concept, and those who argue that “a copy is not you” in particular, engage in. The author shows little doubt about his position although one might object that the central example that is used to make the case could also be used to argue against mind uploading. One might even object that the whole debate involves a pseudo-problem if any kind of empirical observation can be made consistent with the case for and the case against mind uploading.
Aside from these complexities, this is an admirable effort to raises interest in high quality brain fixation. Initial funding for more experimental research should be encouraged.