Alright, promise me you won’t freak out, but you’re not observing objective reality right now. No, you are seeing the world as your brain interprets it, a world processed and modeled by meaty software honed by billions of years of evolution. It’s a weighty thought, but easily proven. Every optical illusion you’ve ever seen is a hint that what you see and what you perceive are two different things.

The latest video from the YouTube science channel SmarterEveryDay uses a highspeed camera and cleverly programmed, spinning LEDs to make the same point:

As Destin explains, many images that seem persistent, like those from the spinning LEDs or on a television screen, actually have gaps of pure blackness in between, but we never see them. Instead, the brain combines these images into a stream in what researchers call “persistence of vision.” When flashes of images come quickly enough, the stimuli bunch together in the brain and become one. This persistence is the apparent explanation for why movies look like, well, movies, and not still-ies.

Destin makes it pretty easy to understand, but you don’t need a high-speed camera to experience this yourself. Go to a mirror and look yourself in the eye. Then look yourself in the other eye. Did you see your own eyes move? You can’t, it’s impossible. The eye moves too fast to capture enough images in between the start and end point of your gaze. Rather, there should be blackness between those points, but you don’t perceive it. The brain is to blame here too — the world as your brain models it is filled into this perceptual dark. The result is a more fluid, but not more real, stream of consciousness.

OK, you can freak out over that last bit if you want to.

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IMAGES: Smarter Everyday