[derekp7]

The problem (as stated in this article) is that we can't even trust that. Because we only have our memory of what our five senses detect, and these fake videos can alter our memory.

One of the most vivid examples I recall was back in high school, seeing a video that was debunking the myth of "back masking" (having hidden messages when an "evil" metal song was played backwards). They played the same sound clip, with a transcription of the supposed hidden message on the screen, and I could clearly hear that message. Then they played the same clip but with a completely different message on the screen, and I could also distinctly hear that alternate message, in the same sound clip.