A bold claim by Sonke Ahrens - which he argues pretty well. This mindset gives you reasons to learn, which helps you do it.
Having ideas isn’t enough. Writing them down makes them tangible. There is no history of unrecorded ideas. Having the goal to translate what you’re studying, what book you’re reading, or lecture you’re attending into your notes gives you a new purpose when doing the work. You are less likely to succumb to boredom when you know what outcome your attention will give you.