Interesting things often happen to me in the transitional phase between sleep and wakefulness. In that twilight zone where I am neither fully asleep nor fully awake, it seems that the intuitive, creative side of my brain is most active. During that time, solutions to vexing problems (usually related to a writing project) come to me, seemingly out of the blue. Other thoughts also occur to me, often regarding subjects I wasn’t even aware I was thinking about.
That happened again just the other morning. But before I reveal it, a little background.
Whether or not life is inevitable, given the right circumstances, is a problem that has vexed biologists (and philosophers) for some time. Since we only have one example – Earth – it is impossible to draw any firm conclusions. That is one reason why so much effort continues to go into searching for evidence of life beyond our planet. Much of this effort is directed at Mars right now, but there is also considerable effort to identify Earth-like planets around other stars. In addition, the Search For Extraterrestrial Intelligence (SETI) project continues its decades-long search for signs of another civilization. If any hard evidence of extraterrestrial life were to be found, even simple, unicellular life, it would change the equation dramatically.
So far, however, there has been nothing firm. So scientists are forced to base their conjectures on what can be found here, on our own planet. That evidence is certainly suggestive. Bacterial and other unicellular life has been found thriving in such unlikely places as undersea thermal vents, near-boiling hot springs, within rocks in Antarctica, in perpetually dark and frigid Antarctic lakes, and even miles underground. If life can exist in those places, it seems it can exist anywhere.
Many of these places are proposed as the place where life may have originated, since many of them mirror conditions on our planet when it was very young, with its extremes of temperature and anoxic, even toxic, environments. Other scientists propose that life originated elsewhere and the Earth was seeded by bacteria hitching rides on comets and meteors. Recent evidence that some bacteria can survive prolonged exposure to the frigid airlessness of space gives credence to that view. However, that doesn’t solve the problem of how life originated. If it didn’t evolve here but was simply introduced here, it still had to evolve somewhere. Claiming that Earth was seeded just kicks the can down the road.
Nonetheless, based on the foregoing, it seems increasingly likely that life is indeed inevitable. If and when we do discover extraterrestrial life, that argument becomes much stronger. We may be forced to conclude that the physical laws that organize our universe make it impossible for life NOT to develop.
That’s where the “missing factor” mentioned in the title of this post comes in. It was this thought that suddenly occurred to me in my half-awake state: If the physical structure of our universe does indeed make life inevitable, then physicists must take that into account. No theory meant to describe our physical universe could be considered complete without factoring in its propensity to produce life. In other words, the inevitability of life might be as fundamental to the structure of our universe – and as fundamental to the equations that describe that structure – as the relationship between matter and energy or the existence of photons and neutrinos.
I encourage physicists to develop such a theory. Like any theory, for it to be valid it must make predictions that are testable. Equations could be developed that would predict under what conditions and how frequently life would form, based on the known physical structure of the universe. We will continue to search for extraterrestrial life, and sooner or later (if our civilization survives long enough), we will either discover enough of it to confirm the theory, or we will find nothing at all and the theory will be ruled invalid.
I predict the former.