For me to exist, my mother and father had to meet each other, which is a rather unlikely thing to have occurred in the scheme of things. Even assuming that they met, they would also need to mate at just the right time, and then the right sperm (out of hundreds of millions in each ejaculation) had to fertilize the right egg (or which there were many thousands of candidate eggs). But the same thing had to happen to each of their parents, and their parents, and so on. How many sets of parents did this need to happen to? Quite a few–consider my earlier post, “Ancestors Along the highway.” Before all of those parents came onto the scene, the right non-human ancestors had to meet and mate, and before them . . . [skipping way back] the right sponges had to have offspring, and the fungi before them. Had any of these organisms been eaten as prey prior to having offspring, I wouldn’t be here. If any of them had succumbed to disease prior to having offspring, I wouldn’t be here. If any of them had broken a leg or gotten lost in the forest, they might not have gotten around to mating on that critically important date and time (from my perspective). The adventures of Marty McFly (“Back to the Future”) barely scrape the surface.
The seemingly impossible hurdles faced by each of us are addressed by a well-constructed website, “What are the Odds,” which stirs quite a bit of eye-popping mathematics into the description. Wait until you get to the bottom of the page to read about the trillion-sided dice.
Actually, “What are the Odds” overstates the odds that you or I would exist, because there’s far more to being “you” than your biological substrate. If you were raised in a war-torn region rather than a suburban American school, you would be a very different version of you. And ask yourself whether you would be you even if a few of your closest, most influential friends or acquaintances weren’t around to influence you. Or what if you hadn’t happened to read some of the ideas that most influenced you, or if even one or two of those important character-building events that defined you (joyous or tragic or in between) hadn’t occurred?
Thus, it’s almost impossible that you should be here reading this post. Then again, you are here, because all of the antecedent events necessary to make you actually did occur.
I don’t know what lesson one is supposed to draw from this idea that it is essentially impossible that you should be here. Perhaps it’s merely an excuse for a healthy dose of humility. It also seems to me that working through this thought experiment is good for one’s mental health, at least once in a while. I consider it an existential vitamin that I should take periodically.