Your body can tell you're standing blindfolded

Most people think we only have five senses, but you possess a high-speed internal GPS called proprioception. It is the reason you can touch your nose with your eyes closed or walk up stairs without staring at your feet. Your brain constantly receives data from sensors in your muscles and joints that track the exact angle and position of every limb.

This isn't just memory; it is a real-time feedback loop. When you move, your nervous system calculates the tension in your tendons to tell you where 'you' end and the outside world begins. It is so fundamental to your existence that your brain prioritizes this information over almost everything else to keep you from collapsing into a heap.

You only notice it when it glitches. If your leg 'falls asleep,' the nerves responsible for this positional data are compressed and stop sending signals. Suddenly, that limb feels like a foreign object because your brain has literally lost its map of that body part. So what? Without this sense, even the simplest tasks would require 100% of your visual focus just to stay upright.