In The Time Machine, H.G. Wells' Time Traveler character claims that when we recall a moment vividly, we travel back to that time (in "spirit", perhaps). My quarrel, though, is that, in remembering, I don't actually revisit the moment itself, or even my own experience of that moment, but rather my retrospective interpretation of my experience. A year or a month later, looking back, I always simplify and classify my experience and emotions. Nuances are difficult to remember. Ambivalence, ambiguity, half-hearted and unsuccessful attempts to make things go a different way: these don't stick in my memory. They fade out, too delicate to be caught and held, like the photographed rainbow that vanishes into the pale sky on paper.
But when I read my journal, I see the things that ran through my mind as I was still processing, still reeling from whatever happened, still sorting out whether it was good or bad. My journal is a record of events before hindsight imposed a paradigm on them. It's still my interpretation, yes, but it's the interpretation from that very day, a day that I can't re-live but that I can re-imagine. It's a snapshot that retains all its colors, even if it's only one view of the scene.
When I want to travel back, I still try to go in the vehicle of memory, and I see through the haze of my judgment. But when I open my journal and it falls to an earlier page, I fall, too. I fall into a record of my mind, into a moment I had left behind. I find it not as I recalled it, but as it was, with more shading and texture than I could sketch it with now. Fortunately, it's easy to climb back out. Turning pages, I come to a blank one: and I record this moment, too.