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.

What is going on in Kansas

A couple of months ago, I was called by a staff member at the Kansas Board of Education. He said that I was being invited to testify to speak about the nature of science before a committee of their state Board of Education. Since I feel, like most academics, a sense of responsibility to share my thoughts on the topics that I study, I agreed to go to Kansas, thinking that it would be a real sharing of ideas.
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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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Creating the conditions for a just society – 3

According to John Rawls in his A Theory of Justice we have to get together once and for all and make the rules of operation without knowing our particular situation. (See here, here, and here for previous postings on this topic.) And once we make the rules, and then lift the veil of ignorance and find out our particular situation (our gender, age, abilities, skills, talents, health, community, position in society, wealth, income, educational qualifications, level of authority and power, etc.), we are not allowed to renegotiate to get more favorable terms for us. This restriction is important since it ensures that careful deliberation goes into making sure that the rules created are perceived as fair by all.

Let’s work through a specific simple case. People who are generally law-abiding would like to see laws and enforcement mechanisms that ensure their own safety and security and protect their property. If I belong to that category, I might want to advocate stern penalties (fines, imprisonment, harsh prison conditions, torture, even death) for law-breakers. But there is no guarantee that once the veil of ignorance is lifted, that I (for example) will be in the category of law-abiding people. It may turn out that I am actually a crook or have criminal intentions. Normally we would try and exclude crooks from the decision-making process because we have decided that they do not deserve the same rights as law-abiding people. But the veil of ignorance means that we cannot exclude people we disagree with in the rule-making process. I have to consider such possibilities as well when we agree to the rules.

So it is in my interest to make sure that the penalties for law-breaking are not too severe, since there is a chance that I may have to suffer them. Does this mean that crooks will prefer to opt for no penalties at all? No, because even crooks can function effectively only if they are the exception, if there is a general level of law-abiding behavior. After all, the executives who looted Enron and Tyco and caused thousands of people to lose all their savings could only do this because almost everyone else was behaving fairly honestly. This is why crooks can stash their stolen money in off-shore bank accounts and retrieve it later. If the officials in the off-shore banks were also crooks, the stolen money would not be ‘safe.’ Also if the other employees in your own company were not honest, the company would not make the amount of money that makes it worthwhile for you to steal it.

Even petty thieves could not function if everyone around them was also stealing from everyone else with no restriction. And since there is no guarantee that I will be the toughest crook around to fend off the other thieves, allowing for a totally lawless society could result in a terrible situation for me personally if it turns out (once the veil is lifted) that I am not very bright or strong or am clumsy with weapons. After all, there is no guarantee that I will be a skillful crook. An incompetent crook in a lawless society would fare much worse than one in a law-abiding society.

So it is in the interests of even crooks to create rules that encourage and reward honest behavior while ensuring reasonable treatment for law-breakers, just in case they get caught. So the two extremes (law abiding and honest people on the one hand, and crooks on the other) both have an interest in creating rules that balance the interests of both, since no one knows where they personally will end up.

What of the situation that triggered this series of posts, that of gay rights coming into conflict with certain interpretations of religions? Since the rules do not allow you to specify particulars, you cannot say (for example) that the Bible must be the basis for policy decisions. You would have to allow for the possibility for any religious text or that no religious text can form the basis. In other words, if the rules are to allow primacy for religion-based laws, you have to allow for the possibility that once the veil is lifted, you might end up as a Buddhist in a Judaism-based state or a Christian in a Hinduism-based state or you might be a gay person in an Islam-based state. If that should turn out to be the case, would you be content with the result?

Allowing for religious views to be the basis of regulating the private lives of individuals in a society also means allowing for the possibility that we might end up in a society run by groups like the now-defunct Shaker Christian sect, which advocated strict celibacy among its members. Of course, such a society would not likely last very long for obvious reasons (and the Shakers did, in fact, eventually disappear), but would we be willing to allow for this possibility?

Clearly the fact we could end up in any of these situations and have to live with it should cause us to think very carefully about what exactly are the rules of societal regulation that are important to us. I don’t know what specific resolution will be arrived at using the veil of ignorance to address the problem of gay rights and religious opposition to homosexuality. But what I am suggesting is that that is the way we have to address problems such as these if we are to not to just continue to talk through each other, simply asserting our preferences based on our situation and repeating the same arguments.

In some ways, what Rawls is suggesting is that we need to get in the habit of seeing what the world looks like through the eyes of others who may be quite different from us, and ask ourselves whether we would still see the world to as fair from that vantage point. It also requires us to think in terms of universal principles as opposed to principles based on the beliefs and practices of specific groups.

Thinking in this way is hard to do but needs to be done if we are to have any hope of overcoming the differences in policy preferences created by the huge diversity that exists amongst us.

Now clearly those who believe that their vision of God is the right one, and/or their particular religious or secular text is the only source of authority, are going to find it hard to deal with Rawls’ insistence that no identifiable and named groups can be used in formulating the rules. If you believe (for example) that Islam is the one true religion and that the Qu’ran (or Koran) has to be the basis of civil law, I cannot see how you can accept the ‘veil of ignorance’ principle (unless I am missing something). But rejecting this principle also means rejecting the idea of ‘justice as fairness,’ and dooms us to never-ending conflict because people who feel they are being unfairly treated will eventually rise up against their oppressors.

POST SCRIPT

There is an interesting article by Steven Pinker titled Sniffing out the Gay Gene that is well worth reading. I came across it in the excellent blog run by The Center for Genetics Research Ethics and Law.

Creating the conditions for a just society – 2

In the previous posting we saw how people tend to advocate policies based on their own particular background, situation, or preferences, and this necessarily results in perceptions of unfairness over the decisions made.

The key to understanding Rawls’ idea of ‘justice as fairness’ is that people perceive fairness in terms of the process by which results are achieved, not in terms of the actual outcomes of the process. When children play a game and at the end, one child complains that it was not fair, it usually means that the child feels that the rules of operation were either violated or exploited unethically, not that the child should not have lost (unless we are talking about a really spoiled child who feels entitled to always win).

So what Rawls is saying in his A Theory of Justice is that we need to collectively determine the rules by which decisions affecting all of society are arrived at, so that whatever results from that decision making process, everyone will accept that it is fair, although we may not agree with any given decision.

Rawls argues that the essential ingredient to achieving this fairness in process is the ‘veil of ignorance’ under which everyone who is involved in creating the rules (known as the ‘persons in the original position’) operates. What he means by this is:

First of all, no one knows his place in society, his class position or social status; nor does he know his fortune in the distribution of natural assets and abilities, his intelligence and strength, and the like. Nor, again, does anyone know his conception of the good, the particulars of his rational plan of life, or even the special features of psychology such as his aversion to risk or liability to optimism or pessimism. More than this, I assume that the parties do not know the particular circumstances of their own society. That is, they do not know its particular economic or political situation, or the level of civilization and culture it has been able to achieve. The persons in the original position have no information as to which generation they belong. (p. 118)

The veil of ignorance only excludes particular knowledge about the state of individuals or societies. It allows for the kind of general information needed to make meaningful decisions.

It is taken for granted, however, that they know the general facts about human society. They understand political affairs and the principles of economic theory; they know the basis of social organization and the laws of human psychology. Indeed, the parties are presumed to know whatever general facts affect the choice of the principles of justice. (p. 119)

The rules which are arrived at cannot involve identifiable persons or groups or create special exemptions for such groups. For example, if one is making rules about religion, one cannot create rules that apply to a named religious group. You cannot say, for example, that a particular rule will be applied only if the majority of the population (once the veil of ignorance is lifted) turns out to be Christian (or Hindu or whatever.) You cannot also make rules dependent on what the particular situation of a named individual turns out to be. So you cannot say, for example, that the rule of free health care being available to all only kicks in if person X turns out to be sickly.

How would this work in practice? I will see in the next posting by applying it to special cases, including that involving the rights of gays.