A man had walked for miles across bare desert and through thick jungle to find a Guru.

Upon arriving, he walked straight up to the Guru – “Master, I have given up everything and travelled miles across deserts and through jungles to be here with you”.

The Guru asked – “What is that pack that lies upon your back”?

The man replied – “This is the last of my belongings Master, this is everything I have left in the world, I have nothing else but this”.

The Guru stated – “You arrive with the need to tell me all you have done to get here. You claim to have given up everything and yet your claim alone means something to you – as you offer it to me with meaning. If you have all your belongings with you, then you have everything you need and I have nothing to give to you”.  The Guru closed his eyes and went back to meditating without another word.

The man was confused and upset. “But what can I do now Master, I have nothing left” ?

The Guru opened his eyes, gazed upon the man for a few moments and then spoke –
“In return for all you say you have done, I will offer this advice.
Leave this place and return when you have nothing else left – as you have told me that already.
When you have no pack on your back and no claims of what you have done for me, only then will you have nothing left in this world. 
For it is when you experience having nothing, that you will truly appreciate everything that is given to you”.

When you have learnt what is true, you have found only half its Truth.
For it is when you also know what is false, you discover its Truth.

Moral:
To truly know one thing, you must also know its opposite.