Right now, you and living trees are incorporating two kinds of (isotopes of) carbon. Upon your death or the tree’s, the ratio between the two will change as carbon 14 decays to become nitrogen 14, in a process that changes half the carbon to nitrogen in that felled tree over 5,780 years. Because we know that rate of change, we can “radiocarbon” date the time of death. The coupled methods can take archaeologists back about 80,000 years, give or take a week. Through this method even seemingly insignificant tree stumps can tell an accurate tale of the past.
Your personal history is easier to know because there’s a paper or data trail that includes, for example, your birth certificate. Of course, if you were born deep in the Amazon rainforest, you might not have such a trail. And as you know, there are people around the world who have no precise date for their births and no precise calendars of their activities and growth. But if you are a member of an advanced, record-keeping society, you can look up just about every major social step in your life, and you might even be able to see a date on that picture of you sans clothing that your parents took because you were such a cute baby splashing in the tub.
The point is that you can date fairly accurately stages in your life because of objective documentation. Your “tree rings” and “carbon ratio” are exposed, and we don’t have to cut you in half or throw a piece of you into sophisticated analysis to know about stages and events. We just read the date on your high school diploma. Think of that. With the advent of such record keeping, we can lay out your life for anyone, current or future, to know. And even if you choose cremation as your final, though passive, behavior, someone in the Office of Records at your local courthouse will have access to that information, though your ashes might themselves have been spread by winds or water. Semi-permanence lies in all those records. You get to live on in accurate or, because of clerical errors, inaccurate data, even though you might be a minor character among the seven billion current members of the human family and a more minor character among the 100 billion humans that have preceded you over the course of the last 300,000 years or so.
Why “minor”? I certainly don’t want to minimize your worth, but only a very few humans get to the relative level of “semi-permanent immortality” of Ramses, Homer, Caesar, and those other people you studied in history class. In fact, we should all realize that if it were not for the efforts of some to preserve records of those historical characters, their lives would be as substantial as their scattered ashes. Since Herodotus and the like, we’ve been a history-minded people, and going back farther than Homer, we’ve had human idols whose stories we keep retelling. Maybe, though unlikely, a couple or three thousand years from now someone will read about Kim Kardashian or Kim Jong-un. But in reading about either Kim, that future reader will no doubt apply an attitude shaped by personal and cultural changes that are for us unpredictable possibilities.
Since the time when we first became a history-minded people, we have also been a history-revising people. Past human lives are subject to current human ideas and feelings. We just don’t have the objective accuracy of radiocarbon dating or dendrochronology, especially when we try to retell accurately past behavior and events. Seems there’s always some new interpretation based on current intellectual and cultural trends. Intervening contexts make the original context of a life difficult to ascertain.
Unless we are locked into some loop of memory about our own lives, we, too, interpret our personal past on the basis of our personal present. Revising personal history is common because it allows us to write a narrative that fits current mores and metaphors and to satisfy our current desires. Yes, you have an objective record of major events, but in analyzing feeling and assessing detail, you apply today’s subjectivity and today’s standards.
That brings me to ask myself (as it should bring you to ask yourself), “What influences am I currently under that affect the way I now see my past?” Is my introspection as good a guide to my past as tree rings and radiocarbon dating are to a tree’s past? You might think the question is silly, but it involves that aspect of me which cannot be objectively recorded: Feelings.
Changing feelings change how each of us views the past. We don’t have anything in our psyches that is a perfect analog of tree rings and carbon ratios. Once a tree ring forms, it remains a permanent record of the year of growth, indicating drought or abundant rain by its thickness. Unlike us, tree rings don’t undergo changes after their formation. We, in contrast, continuously alter our “tree rings” on the basis of new feelings and altered mores and standards.
That’s why introspection without the context of outside influences isn’t completely reliable. But there’s another problem with a “human dendrochronology.” We don’t always record the effects of our personal and cultural contexts. Take oaks, for example. Dendrochronologists know that oaks produce a ring every year. We’re more like alder and pine: Some years they don’t form rings; some years they form two rings. That’s us.
We know from personal experience and from those who study the human psyche that introspection has some value. It certainly can keep us from repeating mistakes, and it can reveal, if only partly, our motivations. But to be truly indicative of who we were, introspection has to include an assessment of who we are.