Cogito, Ergo Sum
I think, therefore, I am

cogito, ergo sum, (Latin: “I think, therefore I am) dictum coined by the French philosopher René Descartes in his Discourse on Method (1637) as a first step in demonstrating the attainability of certain knowledge. — Wikipedia
Someone wrote a book, so the Titanic went down. Someone started to write a book and 9/11 happened.