If you were alone with your mind would you survive?

Yesterday I watched the film "The theory of everything" that talks about the life of Stephen Hawking and his slow deterioration with motor neurone disease. As I watched it, I thought more and more about what it would be like for your body to slowly give up. Although Stephen could still hear, see , taste, touch and smell the outside world I started to think what it would be like if one were to lose all senses. I imagined a situation where I could not communicate with the outside world, nor could I sense it. I would, in essence, be nothing more than blackness and my mind. And that scared me. How would I cope if it was just blackness and my thoughts, forever.  Would I cope? Would you cope? Could you be allone with your own thoughts for any length of time without going nuts? What are your thoughts like? Are they fun? Could you cope with just yourself?