Your Brain Doesn’t Work the Way You Think

522.057 - 543.05 David Eagleman

So that's how we know we dream during REM sleep. But here's the key. My student and I realized that at nighttime, when the planet rotates, We spend half our time in darkness and obviously we're very used to this electricity blessed world, but think about this in historical time over the course of hundreds of millions of years, it's really dark. I mean, half the time you are in blackness.