the process of being addressed at the time of this writing.16 Finally, what of the use of such technologies by private citizens to spy on each other or to perform independent environmental monitoring?17
Today, prostheses have been developed for replacement of lost bodily function, but in principle, prostheses could be developed to enhance human functions—physical functions such as lifting strength and running speed and sensory functions such as night vision and enhanced smell.
Prostheses are devices that are intended to replace missing human body parts. The discussion below focuses on prostheses that replace body parts that serve physical functions, such as vision or locomotion. Neural prostheses are addressed in the Chapter 2 section on neuroscience.
All prostheses have two components—an assembly (which may be biological and/or electromechanical in nature) and an interface to the human body to which the prosthesis is attached. The assembly replaces the missing part’s function and usually has several components:
• Sensors that provide information to the body about the assembly’s behavior, configuration, and state.
• Receivers that accept information from the body and thus provide guidance to the assembly about the body’s intention for the assembly.
• Actuators that produce the output of that assembly—forms of output are sometimes electrical (as in the case of a prosthesis for a sensory organ) or mechanical (as in the case of a prosthesis for a limb).
• A processing unit that controls the assembly’s operation.
The interface transmits information from the assembly’s sensors to the body’s nervous system and from the nervous system to the assembly. But information flows in the human body are not encoded in forms that are well understood with today’s science. Today, a key factor limiting the development of prostheses—at least prostheses that are integrated
16 For example, the FAA Modernization and Reform Act of 2012 calls on the FAA to fully integrate unmanned systems, including for commercial use, into the national airspace by September 2015.
17 Siobhan Gorman, “Drones Get Ready to Fly, Unseen, into Everyday Life,” Wall Street Journal, November 3, 2010, available at http://online.wsj.com/article/SB10001424052748703631704575551954273159086.html.