When you ask most people what “stereoscopy” means, and you get any answer at all, they usually say something like showing a different image to your left eye and your right eye. But that’s not what it actually means.
When you break it down, “stereo” is from a Greek word for “solid”, and “scopy” is from a Greek word for “to see” or “to look”. So it’s not really about two eyes at all, but rather the idea of seeing solid things.
This explains why one of the more popular and original 3D printing technologies is called “stereolithography”. It’s a word that literally means “solid printing”, which is exactly what 3D printing is.
This distinction may seem subtle, but I think it is one that is going to become more and more important. A stereo movie is a particularly deficient form of “solid seeing”, because it pretty much forces you to keep your head in one place. Moving your head from side to side actually starts to destroy the illusion that you are seeing something solid.
But as we get closer and closer to future reality, synthetic objects will appear in consistent location even as we walk around in the world. When that becomes commonplace, the word “stereoscopy” may no longer be misunderstood. Rather, people will come to understand that it is not really about seeing things with two eyes, but rather seeing the synthetic visions we create as something solid, and accepting them as part of the world we share.