cnat you raed tihs, fi yuo cnat yuo rae dbumer tahn a hsroe's bttu, its aamzngi waht hte hmuan mnid acn do, dnot yuo htink
It's because the human brain doesn't see words as individual letters. It sees them as chains of symbols and shapes. Hence, why you can read blurry text.
Can you read this? If you can't you are dumber than a horse's butt. But it's amazing what the human mind can do, don't you think? Im a genius :3