For those who don’t know, “Occam’s razor” describes a way of choosing between two different explanations for the same thing. It basically means that the simplest explanation is the best one. It was named after a 14th century Scottish scholar/friar (because pretty much all scholars were all churchmen at the time).
It is my observation that Occam’s razor really describes an almost universal human strategy. It is the way human beings approach truth. “Where there’s smoke, there’s fire” is one example of how people apply the principle to ordinary life. This saying basically says the simplest explanation for human behavior is the true one.
The problem with Occam’s razor is when it is used as a way to determine absolute truth, rather than determine what truth is most likely. It’s not unusual for people to use Occam’s razor as an argument-ender (Hypothesis A is simpler, so Occam’s razor says A is true. End of discussion.). The problem with this is that the principle is only as good as the data we have. More data can change what the simplest explanation is. What we thought was the simplest explanation can turn out to be very complicated.
For example, for most of the period that human beings have been around to contemplate the world we live in, most people believed the sun revolved around the earth. That was the simplest explanation. Until the 16th century, it was, in fact, the explanation demanded by Occam’s razor in almost all human societies.
What changed? More and better data. Europeans realized that the model of the universe they were using didn’t explain the movements of the planets well enough. If all the planets revolved around the earth, they didn’t stay in nice, neat orbits. The geocentric model of the universe became more and more complicated. Copernicus put the sun at the center and the motions of the planets were all described by nice, smooth paths. More data made a heliocentric model of the universe the simplest explanation and it was eventually adopted by everyone (until it became clear that the sun was not the center of the universe, either).
The amount of data we have today makes a geocentric model completely impossible (the few people who claim to doubt it are obliged to say the data is false). We have sent people to the moon and machines to the farthest reaches of the solar system. We have taken so many photographs and measurements of objects in space and of the earth from space that a geocentric model of the universe isn’t even an option. It’s easy to forget that there was a time when the simplest, most scientific explanation for the motion of the sun, moon, planets and stars was that everything revolved around the earth.
When Copernicus first described his theory, there was nowhere near as much data available and only experts knew the data existed. At first, Copernicus’ model was only highly probable, not proven, and non-experts had little or no reason to believe him. We judge the critics of Copernicus and Galileo a bit too harshly.
There is also a flaw in the human mind. People have a hard time with concepts like “almost certain,” and “highly probable.” Human beings see them as meaning the same thing as either “true” or “false,” depending on what they are inclined to believe. If you are willing to believe an idea that is “almost certain” or even “highly probable,” you will probably see “highly probable” as being the same as “true.” If you really don’t want to believe an idea, you will probably focus on the inherent uncertainty in the term “highly probable” or “almost certain” and say that the idea is “false.”
This is a problem in science, for both scientists and the public, since science rarely declares an idea to be completely true or false at first. In most cases, science initially rates ideas as being “probable,” “unlikely,” “highly probable,” etc. Scientists themselves often take sides in scientific debates and talk about their side as if it were “true,” while scientists on the other side talk about it as if it were “false.” We can hardly expect the public to be more nuanced than scientists are themselves.
As scientists accumulate more data, their ideas stop being “probable” and become either “highly probable” if the evidence supports it or “not very likely” if it doesn’t. Then—if we’re lucky—more data will show the idea to be either “proven” or “disproved.” This has happened again and again. It is how science works, as a whole.
Take evolution. The amount of data Darwin was working with was fairly small, but over time, biologists described more and more species and archaeologists dug up a seemingly immense number of fossil, with approximate dates provided by dating methods that have themselves gained more and more certainty as more data has been accumulated. Biologists examined minute cell structures under the microscope and then geneticists added in DNA evidence.
The amount of evidence that supports evolution is now staggering, with much of that evidence discovered in the last 50 years. Of course, not everyone believes it, for the same reasons human beings rejected previous new ideas: they don’t know the evidence and hearing any uncertainty about an idea they really don’t like is the same as hearing that it’s false.
Of course, not every idea in science is proven to be true. Some are quietly forgotten as new evidence shows that they aren’t just unlikely, but false. For example, scientists used to declare that there was a sharp division between animal intelligence and human intelligence. That difference is slowly blurring as scientists accumulate more data. New evidence always seems to contradict that idea, rather than confirm it. The idea that there is a large gap between the intelligence of human beings and that of all (other) animals is headed for the dustbins of history.
This does not bother scientists because science is supposed to be the best description we have of the world around us and how it works, and science is always evolving. That’s the whole point of doing it. Some ideas in science are now beyond dispute, but others are not. The disputable ideas are the ones scientists love investigating and arguing about, by the way.
Religion is not science. Religion does not purport to be “the best description of the world available,” but “the truth.” It also makes claims about things that cannot be investigated, proven or disproved. That’s the whole point of religion. “Highly probable” is not an acceptable level of certainty in religion. Religion is supposed to go beyond the available data.
Religion is, indeed, a matter of faith. For the believer, it is a matter of knowing true things that cannot be discovered by science. In a religious context Occam’s razor becomes unhelpful because it describes what is most likely true, given the available data, while religion is supposed to describe what is true, without any available data. That is the very definition of faith.
For example, does evolution disprove the Bible? Some people believe that it does, but many others believe that it does not. These believers do not see the question as being “Is the creation story in Genesis true or false?” but rather as “Can the Bible be true even if the creation story is false?” or “Can my religious beliefs be true if the creation story in Genesis is false?” Millions of people have decided that the answer to one or both of those questions is yes.
For the religious, it is not a question of what is most likely, but of what is possible. Religious people arrive at their beliefs through methods that are not subject to scientific investigation. When they use science and evidence to test their religious beliefs, their question is not usually “Is it likely that my religious beliefs are true?” but “Is it possible that my religious beliefs are true?”
While specific beliefs of religion can be proven or disproved, the scant evidence surrounding religious belief almost always leaves some uncertainty in general matters, enough wiggle room for people to say “Yes, my central religious beliefs can be true.” For true believers, the possibility that their beliefs are true is all they need, since they didn’t base their belief on physical evidence in the first place and never expected to have proof of them.
That’s the attitude they have if they’re objective, which most people aren’t. Most people will do the same as they do with science, except it kind of works in reverse. When people want to believe in a religion, any uncertainty about evidence that contradicts it will make them see that evidence as “false,” but when people don’t want to believe in a religion, any evidence that “very probably” contradicts it will be seen as “certain proof.” Believers will think the evidence is irrelevant, while doubters will think that the belief in question has been as thoroughly disproved as the idea that the sun revolves around the earth.
In sum, Occam’s razor is a useful tool, but it is not the same as proof. When applied to faith, it loses its usefulness. In addition, the human emotions surrounding religion will cause most people either to exaggerate what it says or ignore it entirely.