When we make reference to ``CHI'' (Computer Human Interaction) we call attention to the boundary between humans and computers --- CHI becomes a self-fulfilling prophecy, emphasizing this boundary. A goal of `existential computing' is to eliminate this artificial (unnecessary) boundary by ``becoming'' the computer, rather than merely interfacing to it.
An example of an existential user interface is the author's `finger mouse'[7] (based on `WearCam' as in input device). (See Fig 1),
Figure 1:
`FingerMouse':
(a) Early prototype of author's `existential computer'
invention with camera.
(b) Back view of author and
apparatus
together with object being outlined (luxo lamp).
(c) What wearer sees through the glasses:
outline of the object that
denotes path of moving finger around in the space between
the camera (taking the role of eye) and the object.
Image is frozen for near-perfect registration.
(Thanks to Thad Starner and Flavia Sparacino for help in
getting XFakeEvents to work for this).