WE should celebrate the Fourth of July because America -- as the greatest product of Western Civilization -- is the greatest country in the world. But it cannot remain great unless we understand the causes of its greatness.

In this age of diversity-worship, it is considered axiomatic that all cultures and countries are equal. Western culture, it is declared, is in no way superior to that of any other, not even to tribes of cannibals. To deny the equality of all cultures, claim the intellectuals, is to be guilty of"ethnocentrism."It is to flout the"sacred"principle of cultural relativism. I disagree with the relativists.

There are three fundamental respects in which Western culture is objectively the best. The core values and achievements of Western civilization -- what made America great -- are:

1. Reason. The Greeks were the first to identify philosophically that knowledge is gained through reason and logic as opposed to mysticism (faith, tradition, revelation, dogma). It would take two millennia, including a Dark Ages and a Renaissance, before the full implications would be realized. The rule of reason reached its zenith in the 18th century Age of Enlightenment."For the first time in modern history,"writes one philosopher,"an authentic respect for reason became the mark of an entire culture."America is the epitome of Enlightenment thought.

2. Individual Rights. An indispensable achievement was the recognition of individual rights. John Locke demonstrated that individuals do not exist to serve governments, but rather that governments exist to protect individuals. The individual has an inalienable right to life, liberty, and the pursuit of his own happiness.

3. Science and Technology. The triumph of reason and rights made possible the full development and application of science and technology and ultimately modern industrial society. Once man's mind was freed from the tyranny of religious dogma, and productive capacity was freed from the tyranny of state control, scientific and technological progress followed. Men began to understand the laws of nature. They invented machinery. They engaged in large-scale production, the creation of wealth. Wealth financed and motivated further invention and production.

In those countries which did not embrace reason, rights, and technology, people suffered (and still suffer) most from both natural and man-made disasters (famine, poverty, illness, dictatorship) and life-expectancy was (and is) lowest. It is said that primitives live"in harmony with nature,"but they are simply victims of the vicissitudes of nature -- if some dictator does not kill them first.

The greatness of America is not an"ethnocentric"prejudice; it is an objective fact. This assessment is based on the degree to which its core values are pro- or anti-life. Pro-life cultures acknowledge and respect man's nature as a rational being who must discover and create the conditions which his survival and happiness require -- which means that they advocate reason, rights (freedom), and technological progress.

Despite triumphs, America is by no means secure. Core principles are under attack from every direction -- by religious zealots who want to undermine separation of church and state, and by intellectuals, who are denouncing reason in the name of skepticism, rights in the name of entitlements, and progress in the name of environmentalism. We are heading rapidly toward the destruction of our core values and the dead end of nihilism. The core values and achievements of the West and of America must be asserted proudly and defended to the death. Our lives depend on them.

Locke, a professor of management at the University of Maryland, is a senior writer for the Ayn Rand Institute, 4640 Admiralty Way, Suite 406, Marina del Rey, CA 90292.