Sunday, July 23, 2006

Occam's razor

In the introduction to my book Skeptics and True Believers, I defined two frames of mind:

Skeptics are children of the Scientific Revolution and the Enlightenment. They are always a little lost in the vastness of the cosmos, but they trust the ability of the human mind to make sense of the world. They accept the evolving nature of truth, and are willing to live with a measure of uncertainty. Their world is colored in shades of gray. They tend to be socially optimistic, creative and confident of progress. Since they hold their truths tentatively, Skeptics are tolerant of cultural and religious diversity. They are more interested in refining their own views than in proselytizing others. If they are theists, they wrestle with their God in a continuing struggle of faith. They are often plagued by personal doubts and prone to depression.

True Believers are less confident that humans can sort things out for themselves. They look for help from outside -- from God, spirits or extraterrestrials. Their world is black and white. They seek simple and certain truths, provided by a source that is more reliable than the human mind. True Believers prefer a universe proportioned to the human scale. They are repulsed by diversity, comforted by dogma and respectful of authority. True Believers go out of their way to offer (sometimes forcibly administer) their truths to others, convinced of the righteousness of their cause. They are likely to be "born again," redeemed by faith, apocalyptic. Although generally pessimistic about the state of this world, they are confident that something better lies beyond the grave.

I was careful to point out that even Jesus might be called a Skeptic ("My God, my God, why hast thou forsaken me?"), and scientists who are invincibly certain of the authority of their science can be counted as True Believers.

Although individual scientists might be True Believers, science can only thrive in an atmosphere of skepticism. Science is open-ended; every truth is held tentatively, subject to change. As Einstein once said, the most important tool of the scientist is the wastebasket.

So -- Skeptics and True Believers: A generalization, of course, but (I thought as I wrote the book) a useful one.

As long as we are generalizing, we might also divide ourselves into Occamists or Anti-Occamists.

Let me explain.

William of Occam (c. 1285-1347) was an English Franciscan friar and philosopher, from the village of Occam in Surrey, educated at London and Oxford, who preached and taught across Europe. He is best know to moderns as the author of Occam's razor, the principle of philosophical parsimony: Never suppose a complex explanation when a simpler explanation will suffice.

Occam was surely not the first to enunciate this principle, but he has been assigned the credit, and he certainly used the principle to great advantage, stripping away superfluous accretions from the philosophy and theology of his time -- an exercise that earned him excommunication from from the Church he served.

Occam's razor is a bedrock principle of modern science. Newton put it this way: "We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearance." And Einstein said: "The grand aim of science...is to cover the greatest possible number of empirical facts by logical deductions from the smallest possible number of hypotheses of axioms." Simplicity. Parsimony.

Someone once quoted Shakespeare to the philosopher W. V. O. Quine: "There are more things in heaven and earth than are dreamt of in your philosophy." The remark was meant as a put-down, a sort of "Yeah, what do you know?" To which Quine is said to have responded: "Possibly, but my concern is that there not be more things in my philosophy than are in heaven and earth." Quine was an Occamist.

On the other hand, I have heard that in an episode of The X-Files, Fox Mulder dismisses Occam's razor by renaming it Occam's Principle of Unimaginative Thinking. Let a thousand paranormal and pseudoscientific flowers bloom. Mulder is an Anti-Occamist.

The Occamist does not look for miracles or the paranormal when a natural explanation will suffice. And when no natural explanation presents itself (as, for example, "What is the source of the singularity that became the big bang?") the Occamist is prepared to say "I don't know." To admit our ignorance of the prodigality of creation is not the same thing as to fill our ignorance with a plethora of gods, spirits, extraterrestrials, auras, miracles, morphic resonances, astral influences, etc. of our own invention.

Or so we were taught by the poor, brown-robed, sandal-clad friar from Occam who was a champion of intellectual humility.

Occam's razor, wisely applied, has proved a royal road to practical, reliable knowledge of the world. Since the time of Galileo, and especially since the Enlightenment, it has been the basis for our health, wealth and general happiness. Occam's razor is our most powerful tool in the battle against the darker demons of sectarian strife, religious triumphalism and pseudoscientific superstition.

Further Reading

The themes of this essay are considered at much greater length in my book Skeptics and True Believers.

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