Guard your thoughts, for they define your actions. Your actions become habits, and your habits reveal who you are.

Prologue.

This began as a single sentence: «Guard your thoughts, for they define your actions. Your actions become habits, and your habits reveal who you are.» I did not write it in one sitting, nor by chance: I carried it in my mind for days, guarding it, trying and discarding words until I decided, consciously, which ones were right. I wrote it out several times before I let it stand. It was later, when I investigated it and went deeper, that I discovered how profound it was: it sent me to read books of philosophy just to understand it, and out of that wonder this book was born. Even so, I did what almost no one does with a sentence they love: I put it under suspicion. I verified it against thirty-five sources in two languages, set its evidence beside it, and only then allowed myself to sign it. Because a sentence is not a book, and a book is not born finished: it is built in the open, with its seams showing.

For years I believed a book was something you finished in private and delivered already polished — like developing a negative in the darkroom and showing only the final print. I no longer believe that. This book is written in the open — on a blog that is at once the quarry and the scaffold— because the idea it defends demands it. If what I claim is that you are what you do today, not what you promise to be tomorrow, then I cannot hide the process and show you only the result: the process is the content.

Writing in the open is not a metaphor; it is a method, and you should know what it entails. Every chapter of this book is built in plain sight: the drafts, the decisions, what I cut and why. Before using an important word, I agree on it with you — that is what the Terms and Conventions chapter is for, a living glossary where each concept is pinned down once, with its nuance and its boundary, and then referenced without being explained again. Around the book grows the rest of the project: the talk I am preparing for a stage, the rehearsals, the notes, the real cases. Pieces that look loose today and, over time, arrange themselves into a whole. All of that is this book thinking out loud, and I would rather you watch it happen than receive only the developed print.

I owe you a warning, and I would rather give it to you on the first page. This is not a motivational book. I am not here to promise that in five years you will be who you dream of being, nor to sell you a ladder of steps toward an improved version of yourself that lives in the future. I am here to argue an uncomfortable, contrary idea with you: that you already are who you are today, in what you think, in what you do, and in what you repeat without noticing. There is no «true self» waiting for you around the corner of time. The one reading this, now, with these hands and these habits, is the only one who exists.

That is why every claim in this book carries its source, its nuance and, when needed, its limit. I am not interested in being right by force; I am interested in having an idea that survives scrutiny. I prefer a defensible idea to a comfortable one. And I prefer to confess where all this comes from: not from a desk or a library, but from a photo lab in Mexico two decades ago, and from a recovery that gave me my life back. The philosophy came afterward, to explain what the body had already learned.

One more compass bearing before I let go of your hand. Further on you will find a chapter of Terms and Conventions; I did not put it at the beginning on purpose: this book will hand you each word at the moment you need it, and back there they all live together for whenever you want to return to them.

Read slowly. What follows is work in progress, and I would rather share it this way — imperfect and honest— than wait for everything to be finished before starting to think with you.