Sunday, September 17, 2006

Through a glass darkly

Pascal's Pensees is a grab bag of platitudes, nonsense and substance, a disorganized sketch of the book Pascal might have written had he lived long enough. (He died at age 39.) But it contains enough nuggets of wisdom to have won a place among Western classics.

One entry I have always liked: "Scientific learning is composed of two opposites which nonetheless meet each other. The first is the natural ignorance that is man's lot at birth. The second is represented by those great minds that have investigated all knowledge accumulated by man only to discover at the end that in fact they know nothing. Thus they return to the same fundamental ignorance they had thought to leave. Yet this ignorance they have now discovered is an intellectual achievement. It is those who have departed from their original condition of ignorance but have been incapable of completing the full cycle of learning who offer us a smattering of scientific knowledge and pass sweeping judgments. These are the mischief makers, the false prophets." (Pensees V:327)

The passage would seem to suggest that the purpose of science -- and indeed all education -- is to arrive at a state of ignorance, but an ignorance that is aware of itself. It took almost three centuries for Pascal's insight to become the common view of scientists. The philosopher Karl Popper wrote: "The more we learn about the world, and the deeper our learning, the more conscious, specific, and articulate will be our knowledge of what we do not know, our knowledge of our ignorance. For this, indeed, is the main source of our ignorance -- the fact that our knowledge can be only finite, while our ignorance must necessarily be infinite." The physician/essayist Lewis Thomas went further: "The greatest of all the accomplishments of twentieth-century science has been the discovery of human ignorance."

Science writer Timothy Ferris agrees: "Our ignorance, of course, has always been with us, and always will be. What is new is our awareness of it, our awakening to its fathomless dimensions, and it is this, more than anything else, that marks our coming of age as a species." It is an odd, unsettling thought that the culmination of the scientific quest -- the long slow gathering of reliable knowledge -- should be the confirmation of how little we understand about the universe we live in.

This new awareness of our ignorance should not be taken as permission to indulge the superstitions we are born into. Rather, it should cause us to to be modest and skeptical, parsimonious in our creeds, ever richer in reliable knowledge but ever more demanding in the caliber of proof.

If the writers I have quoted are correct, the essence of wisdom is the willingness to say "I don't know." Why is there something rather than nothing? "I don't know." Why are the laws of nature what they are? "I don't know." Why does Bach's St. Matthew Passion reduce me to awed silence? "I don't know." Why does the sight of a Black Swallowtail in the meadow make me smile with delight? "I don't know." What is the meaning of it all? "I don't know."

On the other hand, consider all the questions for which we have answers. Why does the sun go dark at midday? Why does the comet appear in the sky? Why the plague? Why the drought? Why the infestation of locusts? Why the mountains and the valleys? Why the fossils on the mountain top? How did the universe begin? And on and on.

As long as our answers to these questions invoked the gods -- as they did for thousands of years -- no reliable public knowledge was possible. Only when a few curious people said "I don't know" did science begin. Admission of ignorance is a prerequisite of scientific discovery, and by the same token, the more we learn, the more we are aware of what we do not know.

The 18th-century English scientist Joseph Priestley, the discoverer of oxygen, wrote: "The greater is the circle of light, the greater is the boundary of the darkness by which it is confined. But, notwithstanding this, the more light we get, the more thankful we ought to be, for by this means we have the greater range for satisfactory contemplation. In time, the bounds of light will be still further extended; and from the infinity of the divine nature, and the divine works, we may promise ourselves an endless progress in our investigation of them: a prospect truly sublime and glorious."

As Pascal suggested, in our youth we are indoctrinated into traditional tribal beliefs, as various as the tribal gods are various. Many of us live out our lives in thrall to the traditions into which we are born. Others question their inheritance and embark upon a lifetime of learning. The former end up convinced they know everything. The latter end as they began, in ignorance -- but a self-professed ignorance that is sublime and glorious in its tenatively-held and ever-expanding wealth of knowledge.

Further Reading

Blaise Pascal, Pensees.

The quote from Priestly is from the Preface of the second volume of Joseph Priestley's "Experiments and Observations Relating to Various Branches of Natural Philosophy."

Discuss this essay and more over on the Science Musings Blog.