The child Siri Keeton was not unique: we’ve been treating certain severe epilepsies by radical hemispherectomy for over fifty years now.^[127] Surprisingly, the removal of half a brain doesn’t seem to impact IQ or motor skills all that much (although most of hemispherectomy patients, unlike Keeton, have low IQs to begin with).^[128] I’m still not entirely sure why they remove the hemisphere; why not just split the corpus callosum, if all you’re trying to do is prevent a feedback loop between halves? Do they scoop out one half to prevent alien hand syndrome — and if so, doesn’t that imply that they’re knowingly destroying a sentient personality?

The maternal-response opioids that Helen Keeton used to kickstart mother-love in her damaged son was inspired by recent work on attachment-deficit disorders in mice.^[129] The iron-scavenging clouds that appear in the wake of the Firefall are based on those reported by Plane et al.^[130] I trawled The Gang of Four’s linguistic jargon from a variety of sources.^{[81], [131], [132], [133]} The multilingual speech patterns of Theseus’ crew (described but never quoted, thank God) were inspired by the musings of Graddol,^[134] who suggests that science must remain conversant in multiple grammars because language leads thought, and a single “universal” scientific language would constrain the ways in which we view the world.

The antecedent of Szpindel’s and Cunningham’s extended phenotypes exists today, in the form of one Matthew Nagel.^[135] The spliced prosthetics that allow them to synesthetically perceive output from their lab equipment hails from the remarkable plasticity of the brain’s sensory cortices: you can turn an auditory cortex into a visual one by simply splicing the optic nerve into the auditory pathways (if you do it early enough).^{[136], [137]} Bates’ carboplatinum augments have their roots in the recent development of metal musculature.^{[138], [139]} Sascha’s ironic denigration of TwenCen psychiatry hails not only from (limited) personal experience, but from a pair of papers^{[140], [141]} that strip away the mystique from cases of so-called multiple personality disorder. (Not that there’s anything wrong with the concept; merely with its diagnosis.) The fibrodysplasia variant that kills Chelsea was based on symptoms described by Kaplan et al..^[142]

And believe it or not, those screaming faces Sarasti used near the end of the book represent a very real form of statistical analysis: Chernoff Faces,^[143] which are more effective than the usual graphs and statistical tables at conveying the essential characteristics of a data set.^[144]