The irony here is that Kurzweil is a guarded optimist, who, like K. Eric Drexler and Robert Freitas, also imagines that Transhumanism may make things far worse for humanity. The promise is intertwined with peril. Both are far greater(far better and far worse) than the current possibilities. Tech is just an amplifier, often of majority tendencies toward survival (which is why everyone has a refrigerator, but not everyone has a nuclear weapon).