The musician, producer, circus performer, entrepreneur, TED speaker, and author, Derek Sivers, recently wrote an article that began, “You know those people whose lives are transformed by meditation or yoga or something like that? For me, it’s writing in my diary and journals. It’s made all the difference in the world for my learning, reflecting, and peace of mind.”He’s kept a journaling habit for over 20 years. Every night, he takes just a couple minutes to jot down a few sentences to recap his day, how he felt, and thoughts he had. What’s so transformational about that? As Sivers explains:“We so often make big decisions in life based on predictions of how we think we’ll feel in the future, or what we’ll want. Your past self is your best indicator of how you actually felt in similar situations. So it helps to have an accurate picture of your past.You can’t trust distant memories, but you can trust your daily diary. It’s the best indicator to your future self (and maybe descendants) of what was really going on in your life at this time.If you’re feeling you don’t have the time or it’s not interesting enough, remember: You’re doing this for your future self. Future you will want to look back at this time in your life, and find out what you were actually doing, day-to-day, and how you really felt back then. It will help you make better decisions.”Compare that to Seneca:“I will keep constant watch over myself and—most usefully—will put each day up for review. For this is what makes us evil—that none of us looks back upon our own lives. We reflect upon only that which we are about to do. And yet our plans for the future descend from the past.”How often do you consult your past self to make decisions? Could you do so even if you wanted to? Or have most days, most experiences, most feelings, most thoughts vanished from memory? Journaling is a memory bank with unlimited storage. It’s an archive, a reference manual, an unmatched tool for learning from today to inform tomorrow. That’s why journaling is so transformational. If you still haven’t, start journaling today. Start compiling your archive.Do it for your future self.