Parmenides

Parmenides was a Greek philosopher who lived a long time ago. He believed that the universe is made up of one single unchanging thing which always stays the same and never changes. This means that nothing ever comes into being or disappears - everything just is. This would mean that we can't trust our senses to tell us what is true, as our senses tell us that things appear and disappear all the time. But Parmenides believes that this isn't true, and that things always remain the same.