The use of models is not limited to science. Indeed, normative, prescriptive social models predate by many centuries the descriptive and predictive nature models just mentioned.
Beginning in the distant past, cultural codes of conduct--for example, the Code of Hammurabi and the Ten Commandments--were used to govern family and tribal relationships. Other examples of social models include the charters, bylaws, and organizational charts of corporations, universities, and religious institutions.
Governance models of nation-states range from the divine right of kings to fascism, communism, and constitutional democracies. Entrepreneurs and the venture capitalists who invest in their companies are guided by business models that, by examining a range of scenarios based on various assumptions, forecast success or failure in the marketplace.
Sometimes users of social models actually lose sight of the difference between their models and reality. As Alan Greenspan, longtime chairman of the Federal Reserve Board, warned: "A surprising problem is that a number of economists are not able to distinguish between the models we construct and the real world."
When we use parents, heroes, public figures, and fictional characters as "role models," we're using models to shape our character. As will be discussed in chapter, religion gains its special place in human affairs by providing us with models of the self and its transformation.
In sum, models are descriptive or prescriptive representations of the world and ourselves, and they serve a variety of functions. Among these are to provide us a sense of identity, shape our behavior, maintain social order, and guide our use of power. Model building has made us what we are and holds the potential to guide us as we put our predatory history behind us and move into a dignitarian era. To see how models can help us make this transition, we need to familiarize ourselves with the broad features of the model-building process.
Inherent in the notion of building models is that they change. That models are perpetually works in progress is a key reason why they are so useful. But it has been hard to accept the notion that models can and should change, yielding to modified or radically new ones as we gain more insight and information. Until relatively recently we have much preferred to stick to what we know--or think we know--and defer to existing authority and received wisdom. But ironically, our principal heroes are precisely those people who have struggled and suffered to overcome the notion that "the truth" is forever, usually by championing a new truth that contradicts the prevailing social consensus.
A turning point in the history of intellectual development came in the seventeenth century when one such figure, the English physician William Harvey, discovered that the blood circulates through the body. His plea--"I appeal to your own eyes as my witness and judge"--was revolutionary at a time when physicians looked not to their own experience but rather accepted on faith the Greek view that blood was made in the liver and consumed as fuel by the body. In persuading people to see for themselves, Harvey drove another nail into the coffin of Aristotelian fundamentalism, which had dominated thought for more than a thousand years.
As Bertrand Russell, the Welsh mathematician and philosopher, said, "Aristotle could have avoided the mistake of thinking that women have fewer teeth than men by the simple device of asking Mrs. Aristotle to open her mouth." The idea that institutional dogma be subordinated to the empirical experience of the individual represented a critical juncture in human affairs. States quite rightly saw it as a threat to their monopoly on power. In fact, what we like to think of as the unassailable truth is actually just our best current understanding of things--in other words, our latest model. Nothing is more natural than that models should change with time.
Another classic example of the evolution of models was the shift from the geocentric--or Ptolemaic--to the heliocentric--or Copernican--model of the heavens. Until five centuries ago, it was an article of faith that the sun, the stars, and the planets revolved around the earth, which lay motionless at the center of the universe.When the Italian scientist Galileo embraced the Copernican model, which said that the earth and other planets revolve around the sun, he was abandoning the received wisdom of the church. This was considered sacrilege, and under threat of torture, he was forced to recant:
I, Galileo Galilei, aged 70, arraigned before this tribunal of Inquisitors against heretical depravity, swear that I have always believed all that is taught by the Church. But whereas I wrote a book in which I adduce arguments of great cogency...that the sun is the center of the world and immovable, and that the earth is not the center and moves, I abjure, curse, and detest these errors and heresies and I swear that I will never again assert anything that might furnish occasion for suspicion regarding me.
By maintaining that his arguments had "great cogency," Galileo defended his integrity while sparing himself the fate of some of his predecessors. The Dominican friar Giordano Bruno, an Italian philosopher-scientist like Galileo, was burnt at the stake in 1600 for championing the Copernican model. Fundamentalists have never lacked for conviction.
As Galileo withdrew from the court, he is said to have mumbled, "But it does move. "He spent the rest of his life under house arrest, making further astronomical discoveries and writing books for posterity. In 1992 an ecclesiastical commission appointed by Pope John Paul II finally and formally affirmed that Galileo had been right.
The Galileo affair was really an argument about whether models should be allowed to change without the church's consent. Upon the geocentric model rested a whole edifice of theological thought, much of which was also contradicted by new evidence. For example, finding seashells on mountaintops and fossil evidence of extinct species undermined theological doctrine that the world and all living things were a mere six thousand years old. Such discoveries posed a serious challenge to conventional wisdom and the authority of the church. Freeing ourselves from the idea that the world is fixed, immobile, and unchanging marked the birth of modernity.
Galileo's models were later improved upon by Newton, whose three laws of motion form the foundation of classical dynamics. Then, in the twentieth century, limitations were discovered in Newton's model. It works fine for falling apples and for space vehicles, but when applied either to objects moving at speeds comparable to the speed of light or to particles on the atomic scale, Newton's laws give erroneous predictions.
These failings were overcome by relativity and quantum mechanics.