Science, religion, and Ockham’s razor-2

Following up on the previous posting, I want to look at how Ockham’s razor comes in to play in the science and religion discussion.

As I have stressed repeatedly in previous postings, developing a personal philosophy of life can be very rewarding and may be one of the most valuable things we start learning to do in college. But I do not mean to imply by this that people do not have a philosophy already. I think all of us do, at least implicitly. What I am recommending is that we use the many resources of the university to bring to the surface our existing and implicit philosophies and learn how to refine that philosophy.

In that process, the integration of science and religion into one coherent philosophical framework becomes one of the most difficult challenges and there is no simple solution to it. And all of us use Ockham’s razor to resolve it, even though the results are not the same for everyone.

A belief in the existence of God implies that there must be at least some phenomena caused by the intervention of God that lie outside the purview of science. (I am not considering the point of view that God created the world and its laws in one instant of time long ago and then has had a completely hands-off policy since then.)

For example, Biblical literalists will start with the assumption that the Bible is a historical document and that the events described in it (the world was created in six days and is only 6,000 years old, Joshua caused the Sun to stand still, Noah’s flood did occur, etc.) Then they will painstakingly try and reinterpret all evidence to the contrary in the light of these axioms. The website Answers in Genesis goes to extraordinary lengths to try and answer questions such as “Where did Cain find his wife?” and “Did dinosaurs live alongside humans?” These are questions that do not trouble anyone who does not treat the Bible as an authoritative source for science and history.

But even those who take the Bible less literally have to confront difficult questions because at some point, the question is going to arise about where you draw the line and ascribe something to the actions of God. This is something that believers in any theistic religion have to confront.

At some point, if you are a religious believer, you have to postulate that God’s actions are inscrutable and that we cannot know the answers to at least some of the events that occur in the world. Each person will draw the line between God’s actions and the actions of natural laws differently, depending on their personal level of comfort with the explanation.

Some will believe that any event that does not have a ready explanation to hand (a death in the family, an escape from injury, an unexpected recovery from a seemingly fatal illness) are directly due to God’s intervention to change the course of events.

At the other end, others might believe that God does not actually cause a change in the natural sequence of events but instead exerts his/her influence by working through people. In other words, people are the agents of God’s actions and the sole mechanism by which he/she influences events. So people are cured of illnesses because God inspires researchers and physicians, and so on.

There are also an infinite number of intermediate states between those two extremes. For example, people like the biochemist Michael Behe, who is an intelligent design advocate and author of the book Darwin’s Black Box, accept natural explanations for everything except for a few selected phenomena at the biochemical level (such as the blood clotting mechanism or the creation of the bacterial flagellum) that he feels are unlikely to have been created by natural processes.

(See the New Yorker article by H. Allen Orr for a clear description of what Behe’s argument is. Cory also sent me a link to a nice article (written by John Rennie, editor of Scientific American) that addresses some of the key points raised by ID advocates.)

Or one can use decide that there is no God (or supernatural entity of any kind), and all that exists is the material world. This is the position of philosophical naturalism or atheism. (I am treating the two terms as effectively synonymous, although professional philosophers might disagree).

Which position one ends up taken is largely determined by deciding which is ‘simpler’ to believe in, which usually means deciding which belief structure you find personally enriching and meaningful, since there is no unambiguous measure of simplicity for incommensurable theories. So Ockham’s razor is used differently by each person.

In a comment to an earlier posting, Kurtiss made a suggestion: “Imagine that in the normal course of your day, science accurately predicted 95% of the events that took place, but the other 5% had an outcome decided by the god.” Now we can compare Kurtiss’ model with other models in which (say) 100% of the events are attributed to God, or 0% is due to God. There is no way that I know of to convincingly say which of these models is true.

So we are left with only Ockham’s razor with which to make a decision but in this case, it is a very personal razor whose use will satisfy only us. And there is nothing wrong with that. That is what developing a personal philosophy of life is all about, finding something that gives meaning and direction to your own life.

POST SCRIPT

In the first two weeks of May, I referred in several postings to the Harper’s article by Chris Hedges dealing with the influence of the Dominionist movement and the rapture. (You can search this blog under “Hedges” to find those postings.) The Hedges article is now available online here.

Science, religion, and Ockham’s razor

A few days ago I was working in my backyard when I noticed that the outdoor thermometer that I had fixed to a fence had disappeared. The mountings were still there but had been pulled away slightly. I thought that maybe the wind had blown it off and so I looked at the ground underneath but the thermometer was not there. There is a bed of pachysandra nearby and I looked nearby in it but no luck. I was baffled.

I pondered the various options for explaining the missing thermometer. One was that the wind had been strong enough to rip the thermometer from its mounting and blow it farther away into the pachysandra. The other was that it had fallen to the ground below and had then been taken away by squirrels or the neighbor’s cat. The third was that neighborhood children had borrowed it without permission for some experiment. The fourth was that the International Outdoor Thermometer Cartel (IOTC) had raised the price of these thermometers to such a high value that organized crime gangs were stealing them and selling them on the black market. The fifth option was that aliens had taken it away as a souvenir of their clandestine visit to Earth.

Given these options, I decided that #1 was the most likely one and looked in the pachysandra over a larger area, and sure enough. I found it.

The reason for this anecdote is that it illustrates that I used something that we all use all the time (whether we are consciously aware of it or not), and that is Ockham’s razor to make choices among competing theories.

According to the Encyclopedia Brittanica, the principle behind Ockham’s razor (also called the law of economy or the law of parsimony) was stated by the scholastic William of Ockham (1285–1347/49), as “Plurality should not be posited without necessity.” The principle is also expressed as “Entities are not to be multiplied beyond necessity.” Ockham did not himself use the word ‘razor’, that was added to his name later by others.

The principle gives precedence to simplicity, but there are two ways it can be used. In the first case (which is more closely aligned with Ockham’s intent), it says that you should not postulate more elements for anything other than the minimum required. For example, in the case of my missing thermometer, if I postulated one theory that a cat had taken it and a competing theory was that a cat that had a striped tail and a scar on its forehead had taken it, then in the absence of any extra information, the former theory is to be preferred. The latter theory just adds elements that do not add any necessary information to the explanation. The application of this version of the principle is fairly straightforward. One seeks the smallest subset of elements of a theory that provides an adequate explanation of whatever you are trying to explain.

The more problematic (and common) use of Ockham’s razor is when you try and apply it to a situation where there are two competing theories that share no common elements or there exist at least some necessary elements of one theory that the other does not possess. We commonly interpret Ockham’s razor in those situations as requiring us to choose the simpler of the two theories. But simplicity may well lie in the eye of the beholder and it may not be easy to get agreement.

So, for example, in the case of the thermometer that was found some distance away from its mountings, the simpler explanation (for me at least) was that of the wind. If called upon, I could call upon Bernoulli’s Principle and the laws of motion to support my preference. That explanation is simple enough to satisfy me.

But this may not be true for someone else. For them, a theory that alien vandals landed in my garden, tore the thermometer from its moorings, threw it away in the pachysandra and left in their spaceship, might be the “simpler” explanation in the eyes of someone who is a believer in the existence UFOs and space aliens. After all, it does not involve the use of calculus.

That is exactly the problem in many of the science and religion discussions, and we will see that in the next posting.

POST SCRIPT

In a comment to a previous post, Amanda (a former student who graduated a few years ago and is now doing her PhD in astronomy) sent me a link to an excellent New Yorker article that goes straight to the core intelligent design argument, cutting through all the confusion that often surrounds such discussions. The article is well written and lays out the basic premises of ID as well as clears up some popular confusion about how evolution and natural selection work. I strongly recommend the article and gratefully thank Amanda for bringing it to my attention.

Why scientific theories are more than explanations

At its heart, ID advocates adopt as their main strategy that of finding phenomena that are not (at least in their eyes) satisfactorily explained by evolutionary theory and arguing that hence natural selection is a failed theory. They say that adding the postulate of an ‘intelligent designer’ (which is clearly a pseudonym for God) as the cause of these so-called unexplained phenomena means that they are no longer unexplained. This, they claim, makes ID the better ‘explanation.’ Some (perhaps for tactical reasons) do not go so far and instead say that it is at least a competing explanation and thus on a par with evolution.
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Why ID is not science

In the previous posting, I pointed out that if one looks back at the history of science, all the theories that are considered to be science are both (1) naturalistic and (2) predictive. Thus these two things constitute necessary conditions.

This is an important fact to realize when so-called intelligent design (ID) advocates argue that theirs is a ‘scientific’ theory. If so, the first hurdle ID must surmount is that it meet both those necessary criteria, if it is to be even eligible to be considered to be science. It has to be emphasized that meeting those conditions is not sufficient, for something to be considered science, but the question of sufficiency does not even arise because ID does not meet either of the two necessary conditions.
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What is science?

Because of my interest in the history and philosophy of science I am sometimes called upon to answer the question “what is science?” Most people think that the answer should be fairly straightforward. This is because science is such an integral part of our lives that everyone feels that they intuitively know what it is and think that the problem of defining science is purely one of finding the right combination of words that captures their intuitive sense.

But as I said in my previous posting, strictly defining things means having demarcation criteria, which involves developing a set of necessary and sufficient conditions, and this is extremely hard to do even for seemingly simple things like (say) defining what a dog is. So I should not be surprising that it may be harder to do for an abstract idea like science.
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Necessary and sufficient conditions

The problem of finding definitions for things that clearly specify whether an object belongs in that category or not has long been recognized to be a knotty philosophical problem. Ideally what we would need for a good definition is to have both necessary and sufficient conditions, but it is not easy to do so.

A necessary condition is one that must be met if the object is to be considered even eligible for inclusion in the category. If an object meets this condition, then it is possible that it belongs in the category, but not certain. If it does not meet the condition, then we can definitely say that it does not belong. So necessary conditions for something can only classify objects into “maybe belongs” or “definitely does not belong.”

For example, let us try to define a dog. We might say that a necessary condition for some object to be considered as a possible dog is that it be a mammal. So if we know that something is a mammal, it might be a dog or it might be another kind of mammal, say a cat. But if something is not a mammal, then we know for sure it is not a dog.

A sufficient condition, on the other hand, acts differently. If an object meets the sufficient condition, then it definitely belongs. If it does not meet the sufficient condition, then it may or may not belong. So the sufficient condition can be used to classify things into “definitely belongs” or “maybe belongs.”

So for the dog case, if a dog has papers certified by the American Kennel Association, then we can definitely say it is a dog. But if something does not have such papers it may still be a dog (say a mixed breed) or it may not be a dog (it may be a table).

A satisfactory demarcation criterion would have both necessary and sufficient conditions because only then can we say of any given object that it either definitely belongs or it definitely does not belong. Usually these criteria take the form of a set of individually necessary conditions that, taken together, are sufficient. i.e., Each condition by itself is not sufficient but if all are met they become sufficient.

It is not easy to find such conditions, even for such a seemingly simple category as dogs, and that it the problem. So for the dog, we might try define it by saying that it is a mammal, with four legs, barks, etc. But people who are determined to challenge the criteria could find problems (What exactly defines a mammal? What is the difference between an arm and a leg? What constitutes a bark? Etc. We can end up in an infinite regression of definitions.)

This is why philosophers like to say that we make such identifications (“this is a dog, that is a cat”) based on an intuitive grasp of the idea of “similarity classes,” things that share similarities that may not be rigidly definable. So even a little child can arrive at a pretty good idea of what a dog is without formulating a strict definition, by encountering several dogs and being able to distinguish what separates dog-like qualities from non-dog like qualities. It is not completely fool proof. Once in a while we may come across a strange looking animal, some exotic breed that baffles us. But most times it is clear. We almost never mistake a cat for a dog, even though they share many characteristics, such as being small four-legged mammals with tails that are domestic pets.

Anyway, back to science, a satisfactory demarcation would require that we be able to find both necessary and sufficient criteria that can be used to define science, and use those conditions to separate ideas into science and non-science. Do such criteria exist? To answer that question we need to look at the history of science and see what are the common features that are shared by those bodies of knowledge we confidently call science.

This will be discussed in the next posting.

POST SCRIPT

I feel that the American media have not given nearly enough attention to the recently leaked secret and explosive “Downing Street memo” from the British secret service that reveals that Bush intended to invade Iraq all along and lied about it to the American people. Juan Cole says that the memo clearly reveals what has been long strongly suspected.

The Bush administration, and some credulous or loyal members of the press, have long tried to blame U.S. intelligence services for exaggerating the Iraq threat and thus misleading the president into going to war. That position was always weak, and it is now revealed as laughable. President Bush was not misled by shoddy intelligence. Rather, he insisted on getting the intelligence that would support the war on which he had already decided.

Cole’s article, where he lays out the sequence of events, is a must read.

The comparison with Darwin and ID

I am a bit of a veteran of the battles that have been waged by so-called intelligent design (ID) advocates to challenge science in general and the theory of evolution in particular. Although not a biologist, I have always had an interest in both physics and the underlying philosophy of science. In the mid-to-late 1990’s I was in the process of writing my first book Quest for Truth: Scientific Progress and Religious Beliefs (which was published in 2000), and it was towards the end of that period that the ID advocates started getting more vocal, at least in Ohio. I was initially drawn to the discussion because of their claim that ID was a scientific theory, which naturally raises the question of what makes a theory, any theory, scientific. As this was a central topic of my book, I looked into ID ideas, although not in any great depth at that time.
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Catholic and Protestant reactions to Darwin’s ideas

When reading and writing about the Copernican revolution and the religious opposition to it (see here, here, here, here, here, and here for that story in sequence), what immediately struck me were the similarities that that episode in scientific history had to the more recent religious opposition to Darwin’s ideas.

Edward Larson in his book Summer for the Gods from which he has published an extended excerpt points out that (in America at least) there was little formal opposition to Darwin’s ideas from the time of publication of Origin of Species in 1859 until about 1920 or so. (Opposition in England started much earlier and I will explore that question in a later posting.)

So as in the case of Copernicus, there was no religious opposition to a seminal work of science until about sixty years after its publication, and the initial religious opposition once again came from the Protestant camp. Initially, the fundamentalist Protestant movement was focused only on fighting “modernism” in the form of the so-called “higher criticism” which consists of “the study of the sources and literary methods employed by the biblical authors.” Such critical methods are not favored by the religious fundamentalists, who see the Bible as divinely inspired and infallible and thereby beyond any criticism. It was only later that Darwinism came to be included under the modernism umbrella.
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The rise of Catholic objections to Copernican ideas

(For those following the Copernican postings in sequence, I made a mistake. Today’s posting should have appeared BEFORE the one that dealt with The role of Protestant opposition to Copernicus. Sorry about that!)

The last myth that I will address concerning the Copernican revolution is that it met immediate, widespread, and religious opposition from the Catholic Church. This took the form of releasing the full force of the Inquisition against his ideas, which resulted in Copernican Giordano Bruno being burned for advocating those ideas and Galileo being forced to recant his support for Copernicus’ sun-centered universe. This is the view, for example, expressed by Bertholt Brecht in his famous play Life of Galileo.
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The role of Protestant opposition to Copernicus

For many years after the publication of Copernicus’ book De Revolutionibus Orbium Caelestium in 1543, his ideas remained within the mathematical astronomy community. The more popular books on astronomy and cosmology either were unaware of his work or chose to ignore them. But there were a few non-astronomers such as poets who were aware of his work and they ridiculed it for advocating a moving Earth, not because of any ideas of heresy. It was though the poets and other popularizing writers of that time that Copernicus’ ideas became more widely known.
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