Is there a limit to what we can know? This is one of the great questions that have occupied the creative minds of some of the world’s most illustrious luminaries. All of them have been stumped and no definitive answer has been provided. The advance of science (or perhaps more specifically, the advance of technology) is changing the epistemological landscape and the old unanswerable questions about limits to human understanding are being brought to sharp focus.
Enter Marcelo Gleiser and his latest work The Island of Knowledge. The book is a broad treatment of the topic. Gleiser begins at the beginning with a discussion of the earliest philosophers of ancient Greece and highlights their ruminations on the nature of the world and the limits of what we can know about it. The narrative speeds along through history to the quantum age. This isn’t a history book. You won’t find here an exhaustive account of all the philosophers and scientists who have produced some answer to the mystery of knowledge limitations. He spends some time on the history of science and epistemology to ground the book and to show the perennial befuddlement of all attempts to grapple with the topic. Most of the book is spent discussing modern science and the breathtaking weirdness of what physicists and astronomers have uncovered. It is here, in our day, where we see most clearly the answer to the above question. Everywhere you turn, in every intellectual discipline of science, the same answer resounds: Yes, there are limits to what we can know about the world and ourselves.
Gleiser enumerates the findings of various disciplines, particularly physics, astronomy and mathematics, highlighting technological limitations to our ability to observe the universe both at the macro (big bang and expanding universe) and at the micro levels (the quantum world). The implications of quantum physics are especially disconcerting to individuals who want the certainty that comes with absolute knowledge. Gleiser spends most of his analytical-descriptive work on the quantum age.
There will be some readers who will say, when they are told there is a limit to what we can know, “Well duh!” But for many scientists whose lives are informed by an ethic of the search for ultimate answers, a search that will eventually be rewarded, this conclusion will come as a shock—kind of like cold water splashed on the brain. We exist on an island. This fact must be faced boldly and digested for all the import it will have on what one might call the “meaning of intellectual life.”
The final chapter acts as an epitaph to the absolutist’s dream. I will quote one passage at some length as a finale to this review.
It is too simplistic a hope to aspire to complete knowledge. Science needs to fail in order to move forward. We may crave certainty but must embrace uncertainty in order to grow. We are surrounded by horizons, by incompleteness. All we see are shadows on cave walls. Yet it is also too simplistic to consider such limits as insurmountable obstacles. Limits are triggers: they teach us something about ourselves while taunting us to keep edging forward, in search of answers. We push the limits and keep on pushing so that we can better know who we are. The same ongoing growth process that we see in science—forward, backward, but always charging ahead—we should see in each of us, in our individual pursuits. The day we become too afraid to step into the unknown is the day we stop growing. (p.280).It is a grand statement and adds a bit of poetic musing to the final chapter of the book. Allow me two observations. First notice the allusion to Plato and “shadows on cave walls.” Plato, a very keen observer of human nature, prodded his fellow Athenians to reach for the permanent unchanging Forms as the only true hope for knowledge. This world view is passé these days—that there may be some eternal, unchanging realm beyond the mundane—but wouldn’t it be nice. Secondly, it may be the way I read the book and this passage in particular, but I can’t help but think that Gleiser bristles and chomps at the bit as one who cannot quite commit to his own conclusions. The limits to knowledge are chaffing. He vacillates, at one moment saying we are surrounded by incompleteness and at the next suggests it is too simplistic to think these limits insurmountable obstacles. Here then is the human condition, we live on an island of knowledge looking out to horizons we just can’t reach. Odd. Frustrating. And yet the mystery (it seems to me a mystery) enchants the world.