A study, part academic and part popular, of the differences in moral conceptual systems that underlie the conservative-liberal debate. If your baby cries at night, do you pick him up? The answer to that question, suggests cognitive scientist Lakoff (Univ. of Calif., Berkeley), is the single best indicator of liberal or conservative values. Driven by curiosity about how liberals and conservatives can ``seem to be talking about the same things and yet reach opposite conclusions'' and why conservatives ``like to talk about discipline and toughness, while liberals like to talk about need and help,'' Lakoff sets out to discover where the difference lies in the two moral visions. He finds it in models of the family and of family-based values: Conservatives favor the ``Strict Father'' model, while liberals conceive of the family as a ``Nurturant Parent.'' That difference, Lakoff argues, yields systems of logic so disparate that liberals and conservatives cannot even begin to understand their opponents' reasoning on issues like abortion, welfare, capital punishment, and gay rights. That much is, on the surface, reasonable enough. Lakoff's argument steers onto more controversial ground, however, when he suggests that ``conservatives have a deeper insight into their worldview than liberals have into theirs,'' inasmuch as conservatives talk constantly of family values whereas liberals shy from discussions of hearth-and-home morality. The ``new understanding of American politics'' that he proposes, not surprisingly, favors conservative values. Lakoff concludes with the observation that ``public political discourse is so impoverished at present that it cannot accommodate'' discussions of matters like family-based moralities- -unless, that is, liberals and conservatives begin to develop a ``meta-language'' that will enable them to speak of such things. That conservatives and liberals see the world differently comes as no news to most, but Lakoff's look into just why that should be so makes for interesting reading.