The word science is derived from the Latin for knowledge.
In 1686, Isaac Newton released for publication Principia Mathematica, in which he (among other matters) gives compelling (mathematical) arguments for his theory of universal gravitation. Almost simultaneously, John Locke published A Letter Concerning Toleration, his seminal work from which the West has drawn its principle of the separation of church and state. In a very real sense, these two publications laid the foundation for the world we recognize today. This foundation is often called The Enlightenment. Not long afterwards, Adam Smith wrote The Wealth of Nations extending these ideas into the area of economics.
Newtonian mechanics has become so embedded in our thoughts and language that it is very difficult to think outside them. The ideas Newton swept aside now seem ridiculous - it's hard to understand how intelligent people could believe them. It takes a certain amount of mental effort to understand what Ptolemy was trying to achieve, and how well his system achieved it. We have the same problem when we try to understand theories that have supplanted Newton, such as relativity or quantum mechanics. It is easy to invent 'paradoxes' which appear to reduce these theories to absurdity, and quite difficult to find the step of Newtonian reasoning hidden in the modern argument, correction of which resolves the paradox.
John Locke's principles have suffered a different fate. There seems to be an element in human nature that takes offense at anyone who does not agree with us. Perhaps it is injured pride - surely our argument was so brilliant and persuasive that our audience would be persuaded! Perhaps it is irritation at the unwillingness of our listener to make the intellectual effort to follow the argument carefully. If only we could punish them (just a little!) for their laziness! Although the separation of church and state was built into the US constitution in 1787, the desire to punish those who disagree with us still struggles for expression all over the world.
Most people draw the governing principles of their lives from a variety of influences, but I wish to classify them under two headings, science and religion. Both scientists and prophets can be wrong: the distinguishing feature of science is that is has adopted and refined procedures for locating and removing errors, so that slowly but surely the body of scientific knowledge grows in size, power, and usefulness, while there seems no particular change from one century to another in the substance or form of religious controversy.
This ever-growing body of knowledge threatens us in various ways. It is increasingly difficult to acquire a useful understanding of the whole range of knowledge, so an increasing proportion of the population feels inferior for having failed to do so. Also, each advance in knowledge has the potential to conflict with cherished hopes and beliefs. Game theory is a recent example. Actually, most Christian teaching ("who is my neighbor?") is consistent with game theory, but there are a few exceptions ("turn the other cheek"). These inconsistencies are inevitable, and eventually the body of religious teaching is reinterpreted to admit the new knowledge, as the Roman Catholics eventually accepted Galileo's discoveries. The process can be long and painful, as Darwin's discoveries are demonstrating today.
Because science has achieved so much, many call themselves scientists to borrow this stature. Philosophers call themselves 'moral scientists'. Various people call themselves 'social scientists'. (Before Newton, scientists sometimes called themselves 'natural philosophers'.) To understand what science is, we should remind ourselves of what all real scientists would accept as a reasonable definition of a scientific belief: a belief is scientific if the believer can describe an experiment, a particular result of which would cause him to abandon the belief. If there is no such experiment, the belief is better described as religious.
Isaac Newton himself certainly understood the difference. After his theory of universal gravitation was published, his critics (to whom the ideas were as strange and difficult to grasp as quantum mechanics is to us) complained that Newton had not explained why all bodies attracted each other. Newton always replied the same way: "I make no hypotheses." By this he meant that scientific understanding went only so far, and that as a scientist he would not be pushed into making suggestions that he could not test by experiment. Privately, he wrote volumes on the interpretation of the book of revelations and other unscientific matters, but he realized that anything he said would inevitably be judged by scientific standards, so he kept them to himself. Only recently have his private writings been studied, and the full range of his interests explored.
The founders of the USA also understood the difference between science and religion. "We hold these truths to be self-evident, that all men are created equal...." was never intended to be an expression of a scientific belief. No experiment to test this belief was offered. There is nothing wrong with a religious belief: some important questions have no scientific answer available, so we must live our lives on the basis of some religious beliefs. The religious beliefs enshrined in the US constitution have been a significant benefit to the country. John Locke's principles themselves are religious beliefs within this definition.
John Locke's principles can be briefly described as follows: the state must have enormous coercive powers to defend the community from internal and external threats, but the state must never use its powers to punish citizens for not acting in accordance with a religious belief. A church (or any other private organization within the state) may use whatever means it has to persuade people to behave in accordance with its beliefs, but it must have no power of coercion other that of expulsion of the individual from the organization.
These principles sound unexceptionable today so long as they are stated in these general terms, because we have grown up with them, and because traditional religious persecution is quite rare today in the West. Other beliefs have arisen during the 20th century that are not experimentally verifiable scientific beliefs, but their adherents have managed to pass coercive legislation to enforce their beliefs.
First an example of the coercive power of the state being used to enforce a scientific belief. In 1904, George Soper (a sanitary engineer in New York City) determined that an alarming number of cases of typhoid had broken out in households where Mary Mallon had been a cook. (The disease is usually transmitted through contaminated food or drink. Normal hand washing is insufficient to prevent typhoid transmission.) He therefore asked her to allow him to test her for typhoid bacteria. Mary refused, claiming that Soper was stigmatizing her for being an Irish immigrant (although she also claimed to have been born in the USA) and that she had never had typhoid. While Soper was trying to get a court order to force Mary to be tested, she disappeared. In 1907, she was located working at another house when typhoid appeared there. This time she was forcibly tested, and found to be carrying typhoid bacteria. At this point, the press dubbed her Typhoid Mary. The city committed her to an isolation center, and the US supreme court denied her appeal. In 1910, she promised never to work as a cook again, so she was released. In 1914, she was found working as a cook in two hospitals where typhoid had broken out, so she was returned to isolation until she died in 1923.
Mary never believed in the scientific evidence that had labeled her a typhoid carrier. To the end of her life, she maintained that it was all an attempt to label the Irish as dirty. The supreme court apparently understood that Soper had passed the test for a scientific belief - among other things, he had correctly predicted that if Mary's stools were examined, typhoid bacteria would be found.
Contrast this with today's affirmative action laws. These essentially presuppose that men and women have equal abilities in all fields, so that if they achieve different results, it must be the result of 'discrimination', not unequal ability. (In fields where women have always achieved better results, such as avoiding prison time, these principles are not applied.) No experiment is offered to test the presupposition - in fact when the president of Harvard suggested treating it as a scientific theory and subjecting it to experiment, Harvard promptly fired him, showing exactly the same spirit as the Catholic church had done to Galileo.
Emboldened by the success of this violation of John Locke's principles, the political right has also sought to erode these principles, banning stem cell research and funding 'faith-based initiatives'. Each political party has effectively retreated to the anti-Lockian position of "those who disagree with me may be punished, but those who disagree with my opponents should be protected."
Interestingly, sometimes religious reasons are given for actions that can be justified scientifically. Prohibition is one example. Historically, mildly alcoholic beverages had been the only drinks available in Europe that were unlikely to be contaminated with disease organisms. Distilled liquors were so expensive that only the rich could afford to destroy themselves this way. During the seventeenth century, tea and coffee began to be imported into Europe, providing a healthier alternative. In the eighteenth century, technological improvements made both brewing and distillation less expensive, so that the opportunity to abuse alcohol increased. These new opportunities led to men (on average) consuming more alcohol while women (on average) replaced much of the alcohol they had previously drunk with tea and coffee.
Not unreasonably, many women felt victimized by their husbands spending a substantial proportion of their paychecks in saloons, while the wives were 'virtuously' drinking coffee. Nagging their husbands to drink less was not an effective way of enticing them to spend more time at home, so wives looked for other techniques. Passing laws to restrict the behavior of others is always popular, so in the nineteenth century the burgeoning suffragette movement began to interest itself in 'temperance'. For various reasons, churches also saw saloons as particularly undesirable, so they supported organizations such as the Woman's Christian Temperance Union, which apparently saw no inconsistency in invoking the name of the man who first came to prominence by turning water into wine, in a campaign to turn beer into tea.
The religious connection should not blind us to the fact that the underlying impulse was based on a reasonable observation that many men's lives appeared to be obviously damaged by drink, and certainly their performance of the commitments they had made to their wives and children was degraded. There was a perfectly reasonable (i.e. scientific) case to be made for prohibition. The two important questions were whether it would be effectively enforced, and whether it was justified to restrict one person's behavior based on the statistical likelihood that it would lead to damage to another person later on. The latter question in particular was silenced in practice with claims that God wanted prohibition. It was the first question whose answer doomed prohibition.
Today's narcotics laws still awkwardly straddle the church-state boundary. Although a scientific case exists in general for these laws, the ethical questions about justifying the intrusion on personal liberty are still answered with what can only be described as religious zeal. The same accusation of heresy is made against anyone who suggests that the laws are so ineffective, and result in so much violence, that repeal would be a net benefit. The ethical nadir was surely reached when the Bush administration took out TV ads claiming that those who bought illegal narcotics were funding al-Qaeda. Surely a more reasoned stance would be that those who criminalized narcotics were creating a funding source for all enemies of the US. No action of mine will defund the Taliban, but George Bush could do so easily by legalizing the narcotics produced in Afghanistan. Parallel decisions would bring instant peace to Columbia and other countries.