From the Editors
Glow With the Flow,” about the nanotechnology behind the Lycurgus Cup, an ancient Roman goblet, was “liked” by more than 51,000 people on Facebook. Many wondered about the cup’s unique color-changing property, speculating that it was designed to detect poison, so we turned to Logan Liu, who has studied the cup and created new nanotechnology inspired by it. “These comments made me really curious and drive me to prove this crowd-sourced theory,” he said. “Even though we cannot test it in the original Lycurgus cup, we can use our nanodevice for this experiment. Many thanks to readers.” We’ll keep you posted on his findings. “Replaceable You,” about the revolution in bionic limbs and organs, provoked spirited debate. “If being a cyborg means a longer and more active life, then sign me up,” Jason J. Hatfield remarked on Facebook. But Jess Grise said the idea of a bionic body was “kind of creepy.”

We Have the Technology
There are two main reasons that the advances author Geoff Brumfiel chronicles in “Replaceable You” might cause some mental strife. First, in the not-too-distant future nearly everyone you know will likely have some sort of major prosthesis, exoskeleton or artificial organ. Coming to grips with the fact that we will all be cyborgs to some degree will not be easy. Second, prosthetics will at some point become so advanced they will be better than organic limbs. Someone making the decision to swap a healthy, fully functional biological body part for a state-of-the-art prosthesis won’t be far behind. Enhancement is a scary and, for many, seemingly ludicrous prospect. Many people fear and distrust technology they see as changing what it means to be human. But a reasonable and cautiously optimistic approach to enhancements will allow this technology to benefit almost every person on the planet. We’d be crazy not to be excited about that.

Kyle Munkittrick
New York, New York

If we use bionics to help people live a normal life, then it’s an incredible science. Using it to give people an advantage over others could be a dangerous, slippery slope.

Robert Bishop
Grand Forks, North Dakota

Don’t be fooled by the hype. As a longtime amputee, I can assure you that no matter how advanced the prosthetic, it comes nowhere near replacing a real limb. And I’m glad Hugh Herr addressed the issue of insurance fairness for amputees. Most prosthetics are not fully covered by insurance. Federal legislation has been proposed to prevent insurance discrimination against amputees. Lots of innovation, for sure, but a long, long way to go—and an especially long way to seeing that those people who need prosthetics are able to get them.

Kathleen Gustafson
Kansas City, Missouri

Photographer Kieran Dodds said that in order to “convey the spark of life” in the artificial hands on the cover, he ended up “glancing at my own hand a lot.” Maybe Michelangelo did the same when he was painting the creation of Adam in the Sistine Chapel, a mural that looks very much like Dodds’ photo.

Barbara Conrad
Racine, Wisconsin

New Perspective
Your article [“Soul of the Machine”] gave me a new insight into David Hockney’s art. He is hacking the fundamental principle of representational art—the vanishing point, the anchor of our perception of perspective. Now I know why I feel he is messing with my brain.

Peter Bannon
Tybee Island, Georgia

In our September issue, we should have said that hydrogen gas, not hot air, kept the Union’s surveillance balloons aloft. In our July/August issue, we meant to say that David H. McNerney was a recipient, not a winner, of the Medal of Honor.