I believe Tim means to say that the spread of misinformation can be linked to the rise of Flat Earthers. That if we can only trust what we see before us, and we see a flat horizon, we can directly interpret this visual to mean that the Earth is flat. Thus, if we cannot trust our own eyes and ears, how can future courtroom evidence be trusted?

“Up to the Twentieth Century, reality was everything humans could touch, smell, see, and hear. Since the initial publication of the chart of the electromagnetic spectrum, humans have learned that what they can touch, smell, see, and hear is less than one-millionth of reality.” -Bucky Fuller