Monday, June 27, 2011

Ockham's Razor and Theology

Let me start with a story.

A long time ago, a couple of Christians made quite an enemy of the Catholic Church. One was himself a pretty devout Catholic (Galileo Galilei) and the other was a confirmed Lutheran (Johannes Kepler). Both of them had accepted—and furthered—a theory of a third Christian, Nicolaus Copernicus, which claimed that the sun was the center of the solar system. The medieval Catholics did not like this; their philosophies were strongly based upon Aristotle, whose astronomy was Earth-centered, and they had decided that the Copernican theory should be abandoned.

These astronomers were trying to decide between two possible explanations of the solar system: geocentrism (the Earth at the center, as developed by Ptolemy) and heliocentrism (the sun at the center). Both models actually did a pretty good job of predicting the motion of planets.

The geocentric model placed the Earth at the center of the solar system. Around the Earth, all the bodies of the heavens rotated. However, a pesky little thing called retrograde motion meant that some things seemed to travel across the sky, stop, and move the other direction! So Ptolemy had some work to do—and he did it. Ptolemy’s system had everything orbiting Earth. But in some cases, Ptolemy had the body orbiting an imaginary point, which orbited the Earth. In other cases, Ptolemy had the body orbit an imaginary point, which orbited an imaginary point, which orbited Earth. So he cleverly developed a way for everything to still orbit the Earth, and yet explain retrograde motion and predict all the movements of the heavens. This model (with all its imaginary points, its deferents and epicycles) was the model that the Catholic Church and “common sense” accepted.

The other model, the heliocentric model, placed the Sun at the center. Around it, the Earth and all other bodies orbited. This also explained well the movement of the heavenly bodies (Kepler showed that these orbits were elliptical, making the predictions much more accurate). This model was not widely accepted, and in fact shunned by Catholicism.

So we had two different theories, both of which explained the evidence equally well. So why were these three Christians willing to risk the anger of the Church and the scorn of fellow academics by embracing the less popular, when the other was just as effective at explaining the evidence?

The reason was something called Ockham’s Razor (though they probably had never heard that particular term). Ockham’s Razor is a philosophical and scientific principle named for English logician and monk William of Ockham. Ockham’s Razor says, “entities must not be multiplied beyond necessity”—or, more simply, do not add assumptions unless absolutely necessary.

(Aside: The most popular version of Ockham’s Razor is a rather misleading one. In Contact by atheist astronomer Carl Sagan, Ockham’s Razor is stated as, “All things being equal, the simplest answer is usually the correct one.” While more quotable, this is demonstrably untrue. Simpler does not mean fewer assumptions, and often reality is rather complex. For example, take gravitation. Newton’s laws of gravity are much simpler than Einstein’s Relativity! Yet experimentation has shown that Einstein’s Relativity is more correct, and in fact requires fewer assumptions that Newtonian gravitation does. Yet no one would claim that Relativity was simple. (Aside-within-an-aside: A reporter once said to Sir Arthur Eddington, “Professor Eddington, it is said that you are one of only three persons in the world who really understand general relativity.” As Eddington paused, the reporter questioned him as to why. Eddington replied, “I am trying to think who the third person is.”) Just because it is not simple does not mean it is not true; and further, this does not violate the principle of Ockham’s Razor.)

Anyway, the point of Ockham’s Razor is that if two theories can explain the same evidence equally well, you should accept the theory which avoids multiplication of assumptions. Given the choice between geocentrism and heliocentrism, it is clear that the geocentric model requires far more assumptions: you must assume earth is the center; you must assume that some bodies orbit earth while others orbit imaginary points; you must further assume that additional bodies orbit imaginary points which orbit imaginary points; and finally you must assume that some bodies (the “fixed stars”) don’t orbit at all. That’s a lot of assumptions. On the other hand, with heliocentrism, you simply assume that the sun is the center of the universe and everything else takes care of itself. This requires fewer assumptions, so Ockham says it is more likely to represent reality.

So…what has this to do with Christian theology?

Well, I would like to encourage Christians to start thinking in terms of Ockham’s Razor when looking at their theologies. When trying to analyze two theological explanations for the same data (i.e., Scripture), keep in mind that if one multiplies assumptions and the second doesn’t, then the latter is probably a superior theory.

Let us start with an easy example, then move to a more difficult one.

Take drinking, for example. Many Christians—particularly Baptists—are teetotalers, and think drinking is always wrong. Now I do not need to tell the alcoholic of the dangers of drinking! Certainly drunkenness is wrong (as demonstrated by Scripture), and even a sip can be devastating to an alcoholic. But does it follow that—just because abuse of a thing is wrong—that any use of it is also wrong? What of the passages of Scripture that refer to wine? Genesis shows that alcohol was sufficiently potent to get pass-out drunk (think Noah and Lot); numerous Old Testament scriptures refer to wine; Jesus changes water into wine (the “good stuff”, not the weak stuff, which earns Him the approval of the party-goers); the Lord’s Supper refers to serving wine; Jesus tells His disciples that they will drink wine together in heaven; Paul chastises the Corinthians for getting drunk on communion wine; and Paul recommends wine to help with indigestion.

There are two approaches to these Scriptures. Teetotalers argue that New Testament wine is always grape juice (the method of making alcohol either having been lost between OT and NT times, or all New Testament writings just being exceptions); they will usually likewise argue that Paul was telling the Corinthians not to exercise restrain but abstinence, and that he didn’t really mean alcoholic wine for tending to stomach issues. Non-teetotalers will say…the Bible says wine, so it was wine.

So you have two theories. One requires numerous assumptions; one requires none. By Ockham’s Razor, I reject the teetotaling theology and accept the alcoholic one. (FYI: I’m not a drinker; don’t care for the taste. So don’t think I have an axe to grind here.)

That was an easy one. How about a harder one? Let’s look at Matthew 24, the Olivet Discourse. In it, Jesus says that the Temple will be destroyed. He says that it will happen during the lifetime of some of His hearers. He says that it will signal the end of an age.

Now there are two primary theories here. I don’t want to get into a lot of eschatology (which I generally find tiresome and pointless), but suffice it to say that two groups (historicists and preterists) say that this has already been fulfilled, while the other (futurists) say it has not. The first theory says that Jesus’ words were fulfilled during the Jewish-Roman War. The Temple was destroyed in 70 AD as He said, and some of His listeners were still alive. The end of the age to which He referred was the end of Mosaic sacrifice—the end of the Jewish way of life. The second theology (the futurist one, as you might read in Left Behind) says that these events have not been fulfilled; the end of age being the end of time. So this requires the Temple to be rebuilt (so that it may be destroyed again). When Jesus told His disciples that some of them would still be alive, what He meant was that “it could happen any time, so be ready”; this is called the doctrine of imminence—that He had to say that to them because He wanted them to stay “on their toes”.

So again, we are faced with a decision. One approach requires a single assumption: when Jesus said “end of the age”, He meant the end of Mosaic Judaism. The second approach requires other assumptions: the Temple destruction was not the one He was talking about; another Temple will be built in the future and destroyed; Jesus told a “white lie” (or was wrong) about the timing being within their lifetimes for the greater good; the doctrine of imminent return is necessary.

Two theological interpretations—one requires only one minor assumption. The other requires a multiplicity of major assumptions, some of which have profound theological influence (such as Jesus lying to His disciples!).

So what do we do? I will tell you what I do—I use Ockham’s Razor. The solution which allows me to read the text, in its context, and accept it just as it is…that is why I believe the Olivet Discourse referred to the end of the Mosaic Code and the 70 AD destruction of the Temple. Because no assumptions are required to be multiplied.

So when you hear your preacher teaching on a passage of Scripture, or read a theological interpretation of a difficult passage, ask yourself this: what are we assuming to be true here, and are these assumptions being needlessly multiplied? Is there an interpretation which does not require us to multiply our assumptions? If there is, then err on the side of choosing that one. It is not always the safer road (just ask Galileo!) but it is far more likely to lead you to the truth

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