The article ends with the "observation" or "claim": "We spend most of our lives pointed forward, peering into the future to see what’s coming, planning how we’ll respond. A notebook looks the other way, and knows how all that ended." Perhaps! But however that may be, this passage reminds me of Kierkegaard's quip in an entry in his Journal of 1843, where he finds:
It is perfectly true, as philosophers say, that life must be understood backwards. But they forget the other proposition, that it must be lived forwards. Anf if one thinks over that proposition it becomes more and more evident that life cannot be understood in time simply because at no particular moment can I find the necessary resting-place from which to understand it - backwards."
I am not sure about that alternative either. In any case, even if I agree with Kierkegaard that it is simply false that "life must be understood backwards" (whatever that may mean), old notebooks help me understand what I was concerned with in the past. This understanding is done from the perspective of the present. That's why I find it a good idea to revisit old notebooks every few years.