Zed A. Shaw, Painter

Here's a challenging thought experiment: What is the most modern technology that you could go back in time the farthest and still make? Ex: I think I could go back about 500 years and make: A simple camera. An electric battery. An electric guitar (but not an amp). You?

Thinking about the camera, I think it'd be possible to go back even farther. I think you could go back to the time of the Greeks or Egyptians and possibly make it. I think you could definitely go back 2500 years and create it in China.

So then the followup to this thought experiment is: If an expert from our time could go back 500, 1000, 2500 years and create a piece of modern tech, then *what* prevented that culture/location from figuring it out? There really isn't much in a camera but, nobody made one.

Take a camera: People have been making glass for a long time, and you can just find glass anywhere there's sand and lightning or heat. A box. Yep, that's not hard. Pinhole cameras were known for a long time. Paper? Wood? Film, now *that's* the tricky part, but, just a camera?

Well and Camera Obscuras are from ancient times. So at some level “they did” is the short answer not involving film.