In recent years, debate has grown over the young field of evolutionary psychology Scientists in this field attempt to explain man behavior through the theory of evolution, which was proposed by Charles Darwin in the mid-1800s and bolstered in the 20th century with the discovery of the genetic basis underlying all living things.    How does the field work? Consider the phenomenon of jealousy, which appears to be universal in human societies. Evolutionary psychologists would reason as follows: Suppose there are two men. One of them carries a jealousy gene which makes him irritable and nervous when he detects signs that his wife's affections have been captured by another man. The other man doesn't carry the jealousy gene and pays little attention to whether his wife is remaining faithful. On average, these scientists reason, the jealous man will have more offspring because his watchfulness makes it less likely that his wife will leave him for another man. In this way the jealousy gene spreads to a greater proportion of the population until, after many generations, just about everyone carries it. Similar reasoning has been cited to explain a wide variety of human emotions.    Evolutionary psychologists feel there's also a genetic basis for that age-old battle of the sexes―the conflict over long-term commitment in relationships. Women, psychologists theorize, are more likely to pass their genes down to future generations if they make an effort to find a mate who will commit to the relationship and help in raising the children. However, men may have different priorities. Scientist Jared Diamond says it's a “cruel fact” that “the male’s genetic interests may not necessarily be in the interests of his female co-parent”.   Net everyone agrees with this approach to science. One view holds that the evolutionary psychologists' conclusions could be used to justify immoral behavior, although they respond that they are merely describing reality and don't necessarily approve of it. Critics also assert that the evolutionary argument sometime amounts to circular reasoning―in other words, it assumes what it is trying to prove. An emotion such as jealousy may spread through culture rather than through genes as children learn from their parents and those around them, these critics say. Stephen Jay Gould, an expert of dinosaur evolution, has accused the evolutionary psychologists of concocting “just-so stories.” What Gould means is this: While scientists may be able to demonstrate the theoretical possibility that evolutionary pressures explain emotions, they are still a long way from actually proving the point. “There is remarkably little empirical data in books by evolutionary psychologists;” charges sociologist Alan Wolfe.   The debate is sure to heat up in the future, for few subject pique our curiosity so much as the origins of the emotions we also are.