The tale of Icarus tells of a young man who flew too close to the sun and fell from the sky when his wings melted. It's a tale of caution, warning us to remember our limitations. Seth Godin, through a video created Squarespace, want you to know this is a load of crap.
Knowing your limits creates a ceiling for your accomplishments. It's especially silly because you can't actually know where any barrier on your personal abilities actually lies. We find out what we're capable of by pushing those perceived limitations and taking the risk of flying too close to the sun. Sometimes we'll fail and sometimes we'll succeed, but we'll always learn from the process.