THIS BOOK ASKS: Why is it that the political enfranchisement of women has not led to substantive equality between the sexes? It answers that question through a detailed study of four political philosophers whose ideas on the rights of man have profoundly shaped our own. Their views of women have been "functionalist," i.e., they have asked not "what are they like?" but rather "what are they for?" And their thoughts have dominated Western political thought, thereby depriving women forever of the common humanity upon which real citizenship depends.

Plato, Aristotle, Rousseau, Mill. All four were concerned with liberty and equality; all four believed passionately that education makes human beings; all four held ideas that moved Western thought steadily forward toward the denial that some human beings are fitted by nature to serve others. Yet the first three turn themselves inside out -- often arguing against their own insights -- to declare women unfit by nature for political equality, and the fourth -- justly famous for his defense of women's rights -- cannot go that last mile in granting all women at all times the equality of life he unequivocally grants men. Why?

It is because none of the four can or will get past the conviction that the family, rather than the individual adult, is the central institution of higher human life. And within that institution it is a given that man must rule and woman must serve. Therefore -- regretfully or gleefully -- all conclude that it is finally, in the nature of things that woman's subordination is ordained.

Although John Stuart Mill would dissent hotly from Aristotle's contention, as Okin puts it, that "nature, who makes nothing in vain," would not "have given woman full rationality when her function does not require it," he cannot take his belief in woman's innate equality to its logical conclusion any more than could Plato. (Although Plato, for one moment in The Republic, saw the truth of woman's equality, he backed off from it.) In order for women to become completely equal, the family as it functioned -- then even as now -- would have had to cease; and for all philosophers that constitutes intolerable loss. It touches a source of personal fear from which they have all drawn back, and which has caused them -- with the monumental skill of powerful minds -- to create a myth by detached analysis.

The chapters on Rousseau in Women's in Western Political Thought are particularly rich because it is here, in Susan Okin's thorough explication of the 18th century egalitarian's writings on women, that we see the fundamental vulnerability of self that is the real and shameless root of female repression. When Rousseau says (as he to the rule of a loving husband (this from the man who burned over inequality!), and that this nature serves the inalienable right of a man to know that his children are his and his alone (thus allowing him to hold his head high in an endlessly humiliating world), he reveals the insecurity of ego which sexual anxiety serves. It is in the name of this insecurity that domestic tyranny is not only excused but idealized, and it is for its sake that that woman is to be deprived of an adult self until the end of recorded time. For Rousseau there is no recognition, ever, that the family system through which shore up their fragile sense of personal power depends for its very life on the insistence that women are unfit by nature to take a place in the larger world.

Most effective, and most shocking, are the final chapters of Okin's discussion in which we see the legacy of "functionalism" still operating. Having spent 300 pages in the past we come suddenly to our own time, and there in the words of contemporary psychologists, jurists and social scientists, we hear the voices of Aristotle and Rousseau! Burno Bettelheim insisting: "As much as women want to be good scientists and engineers, they want first and foremost to be womanly companions of men and to be mothers"; Erik Erikson observing that the development of a human being who is a woman turns on the possession of an "inner space"; the Supreme Court deciding a case on the question of exemption from jury duty: Woman is still regarded as the center of the home and family life. We cannot say it is constitutionally impermissible for a State . . . to conclude that a woman should be relieved from the civic duty of jury service."

The patient recital of the obvious illogic with which the philosophers had to argue in order to exclude women from political equality is the heart of his excellent book. Given the generations of scholars who have ignored the obvious, Okin's contribution is tantamount to the child declaring the emperor to be without clothes. Her language is calm, clear, simple and strong, her feminist perspective a line of thought that guides her steadily along like a tugboat steering an ocean liner through the treacherous shallows close to home. Her thesis is not original but what a powerful reminder of revolutionary times her work is. To juxtapose Aristotle and Erikson is to make us feel again how immensely the language of self-description has altered for women, and for men, in these past 20 years. This book is a contribution to the literature of social change. Insight and catharsis are not enough. Change turns on learning and re-learning -- ever more deeply -- what we already know.