Is not what you think about it.
Rather it is, and it isn’t.

Think about it. As soon as I say the word ‘philosophy’, something comes to mind.
What is it? What is philosophy?
If it was whatever you thought, then how could I possibly have a word that I’m using that allows you to know what to think about ?
How would you know what to think about philosophy if it was what you think about it?
If I said I know what philosophy is, how could you know what to argue against?