Life, craps, and pinball
Take a look at the gallery image on the top left and perhaps you will agree that this is an appropriate time to post it. It is an image of Clarence (left) and George Bailey; Clarence, you may recall, is George Bailey’s guardian angel in the 1947 holiday classic It’s a Wonderful Life. In a fit of despair George says he wished he’d never been born and that folks would be better off had that been so. Clarence takes his cue and proceeds to show George what life in Bedford Falls would have been like had he, George, never been brought into the world. And all of this with the dramatic, classically Hollywood, result that George comes to the realization that his life has indeed made a difference in the lives of those close and not-so-close to him. The Earth will continue to orbit the sun … but details matter in the lives of each of us.
Ok, nice story, but what does that have to do with what’s on my mind? In a letter dated May of 1860 Charles Darwin wrote to Harvard Botanist Asa Gray to thank him for forwarding payments from sales of the first American edition of Darwin’s great book, On the Origin of Species by Means of Natural Selection. In the letter Darwin wrote about the difficulties he encountered in his attempts to reconcile the misery and suffering he saw in the world with his view of a beneficent and omnipotent God. He characterizes nature as miserable and in support cites the example of the Ichneumonid wasp, which lays its eggs inside a living caterpillar. When these hatch, the larvae consume the caterpillar from the inside, saving, of course, the heart and nervous system for last so the nutrient source doesn’t die and rot before the developing young can emerge. On the other hand Darwin marveled at the grandeur, beauty, and intricacies of life and admits freely that nature’s beauty must be the result of laws expressly designed by an omniscient Creator. He says he is not comfortable with the idea that brute force may be responsible for life. In the end he is reconciled when he wrote … I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we may call chance. So Darwin recognized that the general mechanics of life follow regular laws but added that the details, the intricacies, must be due to chance. I agree; life’s details are stochastic, or unplanned in the statistical sense such that a purely stochastic system is one whose state is non-deterministic so that the subsequent and related states are determined probabilistically. Once again, nice story, but what does this have to do with what’s on my mind?
The three images which remain relate to what is perhaps the central theme of Simon Conway Morris’ fine text, The Crucible of Creation. That theme is the not-so-rhetorical argument which others have called the Tape of Life Experiment. The experiment goes like this: rewind the history of life back 3.6 billion years to its inception, and then let the tape replay. Some will liken this to a video tape such that if you were to rewind a movie and replay it it would play exactly the same way time and time again. This thought experiment is different however in that it asks that life be taken back to its beginning and allowed to unfold once more, following the same set of natural laws it followed on its first run (which resulted in the world we currently occupy). Not to be too long about this, but some have argued that because each step in an evolutionary sequence is highly improbable and that each of many millions of highly improbable steps is contingent upon each that came before, the likelihood that life would follow the same trajectory twice is zero (this is called Dollo’s Law). Each replay would result in some drastically different, even unfamiliar, world. The image above the pin ball machine is an artist’s reconstruction of the marine invertebrate fauna of 500 million years ago as revealed by fossil discoveries made in the high Canadian Rockies in the now famous rock outcrop called the Burgess Shale. After studying this fauna Morris, like Darwin, recognized that life follows certain rules. Its movement through time is bounded by walls of impossibility, however, and life is canalized: its potentialities are limited. And now let’s consider what the game of pinball may add to all of this. Imagine the ball as an organism or better yet, a group of organisms, and the long surface of the pinball machine as time. The ball starts at the top of the machine and ends at the bottom … the precise details of its movement from top to bottom could perhaps never be repeated in a million, million turns of the game. The movement of the ball is stochastic but bounded by the confines of the machine. Morris argues that no matter how many times you rerun the Tape of Life experiment you will get a world much like this one, because of the boundaries set by the physical and chemical nature of the building block molecules of life here on Earth – but one very different in its details. We would not get this very particular world each time we replayed the tape, but one very much like it, run after run.
I have come to the conclusion that our lives are, in many ways, predetermined by where we live, who are parents are, who their parents were, and a myriad of variables too numerous to list. The details of our lives, however – who we are married to, who we are not married to, what we do for a living, our particular likes and dislikes – are entirely matters of chance and would probably be very different each and every time each of us replayed the tape of our own life. Think about the law-like and predictable aspects of your life and then about the details which could not have been predicted from a knowledge of the former. Think about the unpredictable and stochastic nature of the tortuous twists and turns our lives take as they enfold in stochastic and highly probabilistic ways. So, finally how does all of his speak to what it is that is on my mind? Well, here it is, at last. Every year Joanna constructs a family newsletter that she calls the Pairodox Chronicles. This year she included the web address for this WordPress blog and I was surprised to receive, in response, a follow request from someone who, perhaps unbeknownst to him, played an important and highly probabilistic role in my own life. When I was in high school my mother was of the opinion that I wasn’t busy enough. So she saw to it that rather sit through, what was in her view, an unnecessary hour or so of study hall, I should be signed on for a class in Marine Biology. And so it was. That seemingly innocent and highly stochastic event changed my personal and professional trajectories, and I am glad of it. That single event, that single course and, more importantly, that single instructor, changed the course of my life such that I now sit across the kitchen table from a beautiful and intelligent woman who has endeavored to make me as happy as anyone could. I am content. For, if not for that wee bit of disruption, who knows where I might have ended up? I know for certain that I would not be writing these words. Thanks very much CJS for changing my trajectory. For as we all know, small changes may have profound effects over long periods of time. And to a first approximation, you have made me what I am.