While the OP has probably already figured this out, it might be good for there to be an actual answer in case others are looking for it.

The reason we call this.setState( this.state ) is so that React actually rerenders the page with the new state. If we just set this.state and didn't call this.setState( this.state ), the state variable would change, but React wouldn't know it is supposed to rerender the page.

I hope that helps!

Hi shyarkhalil,

Do you have any experience with JavaScript yet?

There's a great lesson that will shed some light on how "this" works in JavaScript, inside the Beginning Javascript track. If you haven't covered that yet, then I urge you take it before moving onto attempting anything with React.

Here's a good summary of how "this" works, from the Full Stack Javascript track...

Understanding "this" in JavaScript