Riddle Me This #3 Answered

Here is the Riddle one more time:

I roam freely but cannot pass through bone,
wherever you are is my home.
I will accompany you to foreign lands,
and where I dwell you can hold in your hands.
But I can never be held or measured or claimed,
I can never be broken or fractured or maimed.
I help you to speak, I help you to see,
but I am speaking, of course, abstractly.
I am the key to life's mysteries
and I have no emotional boundaries.
My depth is the sea, my reach is the sky,
I'm a part of you, so who am I?


And the answer?


The Mind