Transhumanism
The library's transhumanism cluster splits into two camps that don't realize they're having the same argument. Kurzweil, Bostrom, and Bohan treat the body as a version number — 1.0, 2.0, 3.0 — as if flesh were software awaiting a patch. Kaczynski and Dubos, from opposite ends of respectability, notice the same thing: that the qualities we call human — courage, honor, free will, even the capacity for love — didn't arise from some abstract essence but from the specific pressures of living in a specific kind of body in a specific kind of world. Change the substrate and you don't upgrade the human; you end it and start something else. What's striking is that Toffler saw this in 1970 — his image of "track stars with extra-capacity lungs" and "lovers with sex-intensifying neural machinery" already contains the quiet admission that enhancement is indistinguishable from replacement once you lose the thread of what the original limitation made possible. The transhumanists and the bioconservatives both frame this as a debate about risk. It isn't. It's a debate about whether meaning requires constraint, and neither side will say so plainly.