It's a difficult question of relations between people.
Why?' is always the most difficult question to answer. You know where you are when someone asks you 'What's the time?' or 'When was the battle of 1066?' or 'How do these seatbelts work that go tight when you slam the brakes on, Daddy?' The answers are easy and are, respectively, 'Seven-thirty in the evening,' 'Ten-fifteen in the morning,' and 'Don't ask stupid questions.
That's how you write novels actually. You suddenly hit upon something and you realize this is the path you were meant to take. You'd be a fool if you didn't follow it. Perhaps it's like solving a difficult question in pure mathematics. There must be a moment when the solution is so simple and evident that you wonder why you hadn't come upon it before. When you do come upon it, you know it in the deepest part of your being. It carries its own logic.
Scientific greatness is less a matter of intelligence than character; if the scientist refuses to compromise or accept incomplete answers and persists in grappling the most basic and difficult questions.