Beware the prophets of doom, and many other ''futurologists,'' for that matter. Their projections of where the world is headed are often more a statement of political bias than a sound extrapolation of available data.
This hazard was evident in a symposium held during the recent annual meeting here of the American Association for the Advancement of Science (AAAS). It was a forum where the doom of the Carter administration's 1980 ''Global 2000'' report was once again confronted by the optimism of the ''Global 2000 Revisited'' study led by economist Julian L. Simon of the University of Maryland and the late Herman Kahn.
The symposium, aptly billed as a ''Knockdown-dragout on the Global Future,'' emphasized one important point in its clash of view. People genuinely concerned about the future of humanity and planet Earth should beware of having their thinking manipulated by ''expert analyses'' which are really propaganda for political philosophies.
This does not mean that one cannot learn a great deal from such analyses. But the conclusions drawn and trends projected into the future should be viewed with eyes made skeptical by a knowledge of the analysts' biases.
This particular global-futures debate was initiated a year ago, when Simon and Kahn first presented their study during the 1983 AAAS meeting in Detroit. To recapitulate briefly, the 1980 Global 2000 report, in essence, concluded:
''If present trends continue, the world in 2000 will be more crowded, more polluted, less stable ecologically, and more vulnerable to disruption than the world we live in now. Serious stresses involving population, resources, and environment are clearly visible ahead. Despite greater material output, the world's people will be poorer in many ways than they are today.''
The Simon-Kahn report, using many of the same data, came to a strikingly opposite conclusion, saying:
''If present trends continue, the world in 2000 will be less crowded (though more populated), less polluted, more stable ecologically, and less vulnerable to resource-supply disruption than the world we live in now. . . . Life for more people on earth will be less precarious economically than it is now.''
(The Simon-Kahn study was finally published in May by Basil Blackwell, New York, under the title ''The Resource-ful Earth: A Response to Global 2000.'')
In both the 1983 and '84 AAAS symposiums, Simon attacked the Global 2000 report as propaganda for government intervention and government regulation of resource use and of business. Hence its tone of threatening doom.
There has been little effective denial of that charge.
On the other hand, Simon has been quite open in using his study to promote the virtues of free enterprise. Its optimism reflects the conviction that it is the creativity and hard work of people that will enable mankind to meet today's challenges - people as unfettered as possible by governmental regimentation and bureaucratic planning.
Such political biases inevitably distort the interpretation of valid data on world conditions.
Yet those data can, and do, warn of dangers and provide a basis for action when they are intelligently handled.
Thus environmentalist Barry Commoner of the City University of New York told the symposium that he had come to rescue such use of data from what he called the ''future schlock'' of both the Global 2000 and Simon-Kahn type of studies. He showed by a few examples that economic and environmental data can reveal hidden social costs. Excess use of nitrogen fertilizer pollutes streams without significantly boosting farm yields, for example.
The central issue is what should be done about such problems. It is here that the political bias shows up. Unfortunately, Commoner was also susceptible to this weakness. He finished his presentation by blaming the free-enterprise system and corporate boards for all environmental damage. He denigrated President Reagan as a politician running for reelection on a platform of ''selfishness'' and ''brutality.'' And he accused Simon of making a campaign speech for the President in the guise of scholarship. This is hardly the language of objective analysis.
What, then, are people to make of purportedly ''expert'' trend analyses if they want truly to know where the world may be heading?
To begin with, there is wisdom in the aphorism that ''trend is not destiny.'' Projecting trends into the future is not good statistical analysis, either.
Mathematically, so-called trend curves - straight lines, exponential growth curves, and the like - can be fitted to sets of data. These are useful for suggesting what has happened in the past. But elementary statistics texts warn against extrapolating such curves beyond the data to try to forecast the future.
Only if there is sound theoretical reason for believing that trends represented by the mathematically fitted curves will continue can such extrapolation be used for prediction. In the case of global-future studies, there is no such theory. There are too many factors at work, too many uncertainties, to assume that conditions will not change. Thus such projections are inevitably colored by political bias. This is why two studies of essentially the same data can present such opposing outlooks as do the studies noted here.
The data themselves can be informative. Expert discussion of the data can be instructive. But readers should draw their own conclusions about what those data may imply for the future. When it comes to projections, the analysts seem all too eager to manipulate public opinion to support their underlying political views.