Paradox is an overrated threat. There is...a quality similar to inertia at work. Once an event has occurred, there is an extremely strong tendency for that event to occur. The larger, more significant, or more energetic the event, the more it tends to remain as it originally happened, despite any interference." I frowned. "There's...a law of conservation of history?

Cold Days: The Dresden Files, Book Fourteen (ed. Hachette UK, 2012) - ISBN: 9780748130818