There is a grammatical convention that every verb must have a subject. Nietzsche contests this idea. He says:' a thought comes when 'it' wants to , and not when 'I want it to.'But can thought exist without a thinker?
Where does a thought originate? Obviously in my mind. But what is mind?Is it a thing? A substance?
Mind is the stuff that thoughts and dreams are made of. Mind is holistic. It does not occupy a location. Let me tell you an anecdote: A cosmonaut and a brain surgeon talk. The cosmonaut says I have traveled miles and miles in space, but I have never seen an angel or God.The brain surgeon says: I have performed hundreds of brain surgery, but I have never seen mind. So again where does mind exist?
Let me give an example: There exists a university in Guwahati and there exists a Sunday.Both are correct.But it would be meaningless to place University and Sunday alongside each other and discuss their interrelations. Again it is meaningless if I ask : What stuff is the mind made of?It is as good as asking what stuff your citizenship or Sunday are made of.
Is it a brain cell activity?( I know you are thinking now.)
To talk of mind in a place is just misconceived. It is just like light: sometimes particle(photon) and sometimes wave(Quantum).Sometimes a thought process and sometimes a neural activity.
I have a mind(or for that matter you have a mind) is a matter of faith because neither of us can see each other's.
My mind is not a chattel: it is me. It is my thoughts and experiences. So my blog is 'My mind'.

Let me conclude with the following classical statement:'...to seek self-knowledge is to embark on a journey which ...will always be incomplete.'