The white-hot singularity at the core of the Machine is – ultimately - a fear of death. It's the inevitability of a journey's end and the threat of a question nobody can honestly answer: what does it mean to make the most of a life? How can you tell that you've spent your time well? There is no metric, no answer key at the back of the book. It's a question that I think everyone had to answer for themselves, and hold tight onto that answer with both hands.