The Happenstance of Existence

The mere happenstance of a coincidental sequence of events, put together by the blind works of nature, has serendipitously manifested itself in this fascinating complexity around us today, that only appears to bear the illusion of an orderly calibration of deliberate design. This happenstance of undirected natural processes has led to self-directed sentient beings, pondering upon such questions of deep significance.

The great biologist Jacques Monod, writing of the natural process of evolution, described it as an interplay of “chance and necessity”. He says “pure chance absolutely free, but blind, lies at the basis of this stupendous edifice of evolution.” Absolute random processes embellish the details of evolution and introduce random variations that the process of natural selection then deterministically directs. The process of natural selection is able to extract “from a noise source all the music of the biosphere”. Might humans not have evolved at all, had the process of evolution gone differently? In contemplating this issue, the late Stephen Jay Gould devised a useful metaphor. He pictured the history of life as the videotape of a movie. What would happen if one were to rewind this tape of life and harken back to a point very early, effectively deleting all the evolutionary progression that has occurred, and then rerunning the tape such that it could be shaped by a completely different chain of events? Would a different evolutionary scheme emerge? According to Gould, evolution is a contingent process, replete with countless branches and various possible courses of direction. This means that if we were to play the tape of life once again, we would get a very different set of organisms. The multitude of organisms that exist today represent just a possible outcome of the plethora of others that could have otherwise existed. “Any replay of the tape would lead evolution down a pathway radically different from the road actually taken”, writes Gould. “Each step proceeds for a cause, but no finale can be specified at the start, and none would ever occur a second time in the same way, because any pathway proceeds through thousands of improbable stages. Alter any event, ever so slightly and without apparent importance at the time, and evolution cascades into a radically different channel.”

The Cambrian Explosion represents the greatest evolutionary radiation of multicellular organisms. Millions of animal phyla appeared in that period, 580-500 million years ago.

So, how likely would it be that adaptive complexity and resulting self-consciousness emerge again, if we were to rerun the tape? To Gould, the chances are quite minute, if not probably impossible. Gould harkens back to the Cambrian explosion, upon which major designs of all multicellular life are based off, to expound upon this. The Burgess Shale is a fossil bed in British Columbia, Canada that preserves the best record of Cambrian animal fossils, which are 500 million years old. Among these fossils, there exist 25 different anatomical basic plans. Only four survived to have modern descendants today. However, any of the 25 different basic plans could have equally led to distinct phyla, had they survived. “If the human mind is a product of only one such set, our origin is the product of massive historical contingency, and we would probably never arise again even if life’s tape could be replayed a thousand times….The history of multi-cellular life has been dominated by decimation of a large initial stock, quickly generated in the Cambrian explosion”, writes Gould.

Burgess Shale fossils. Most animals did not survive to leave modern descendants. Credit: Smithsonian

But how important is the mere occurrence of happenstance if we were to take it to a more retrospective level? Would we exist today if it weren’t for the chance dominance of matter over antimatter at the beginning of the universe? At the beginning of the Big Bang, there were equal amounts of matter and antimatter. However, everything we see around us today is made almost entirely of matter. We don’t observe much antimatter around us. At the first ten-thousandth of a second after the Big Bang, the universe expanded and cooled. Matter and antimatter were annihilating together into photons. Something happened to tip the balance. Due to an asymmetrical chance occurrence, there was one extra particle of matter for each billion matter-antimatter particle pair. As the universe expanded, this residual matter coalesced under gravity leading to solid matter. If it weren’t for this chance asymmetrical mechanism, all the matter and antimatter would have annihilated together leading to a universe of photons and we wouldn’t be here.

Antimatter can be detected in cloud chambers. Particles and antiparticles curve in opposite directions. Credit: Science Photo Library

Rerunning the tape of life more forward, would we exist today if it were not for the chance collision of a Mars-sized planet with the developing Earth, belting out debris that were captured by Earth’s gravity to coalesce into our moon? In its later stages of formation, Earth was indeed lucky that it had grown to a large enough size such that it was hit by a colliding protoplanet to eventually lead to the formation of the moon. The formation of the moon was indeed quite significant because it stabilised Earth’s obliquity (the tilt angle of Earth’s axis relative to its axis around the sun) – an effect, without which, there would have been pronounced variations in climatic and atmospheric patterns, with potentially serious ramifications for life. The collision was large enough to account for the 23.5 degree obliquity that Earth exhibits, which leads to the seasonal variability that life thrives upon.

Could the processes that led the formation of Earth otherwise have led to the formation of planet with a differing chemical composition, accompanied by alternative ramifications for whatever life that might then be able to evolve?

Rerunning the tape of life even more forward, would we exist today if it were not for the chance collision of an asteroid impact, wiping out the dinosaurs and giving way for the diversification of mammals and the evolution of man? What would have happened if that asteroid had missed Earth and spared the dinosaurs in the process?

It seems that all we see around today us is the result of some sort of happenstance of unintentional processes that led to the universe and life as we know it. That eventually led to sentient conscious beings reflecting upon their origins and musing on such profound questions. Beings who would eventually take destiny into their own hands, understand the natural processes that created them, and leave footprints on another world.

We are all extremely lucky to be alive.



Jacques Monod, Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology (New York: Vintage, 1971).

Stephen Jay Gould, Wonderful Life: the Burgess Shale and the Nature of History (New York: Norton, 1989).





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