WELFARE is the great puzzle of puzzles in social policy.Some of its intricacies were described in this newspaper recently by staff writer Nicholas Lemann. He wrote of a Philadelphia family that was in worse financial condition when a teenage daughter found work than it had been when the girl had no job. When the girl found work, the family could no longer qualify for welfare payments and the social programs (Medicaid, etc.) that go along with it. In addition, the teen-age daughter, struggling for her own independence, was not contributing her new earnings to the household -- and wouldn't. In an ideal world, a daughter who found a private route of escape from her family's welfare dependence would be a model of virtue and generosity. But in the world we live in, she was not and, in some ways, is hurting the family that raised her.

The main function of any welfare system, of course, is to support people who are not able to work because of age, handicap, etc., and children who have no source of support. And in addressing those needs, the existing welfare system often does well, or at least does what is minimally required of it. But the system is not good at getting people off a welfare dependency. It can breed conditions that perpetuate that dependency. Still, the goal of establishing a welfare program that can help people on welfare to get jobs is not totally out of reach. The federal government has a program, the Work Incentive Program, that does help people to look for jobs, offers job training and in some cases even provides government-subsidized jobs.

Unfortunately, relatively few welfare recipients are able to participate in the program. And most of those who do get only a quick appraisal of their skills and the benefit of a perfunctory job search. Those who are able to get into the program and make full use of it, however, show a high proportion of success -- about 50 percent. Since there is not enough money, currently, to expand the program so it can be of help to more people on welfare, some who could benefit from it are left out. According to a government study of five million people receiving welfare, about 60 percent of those people could be working but cannot find a job.

The functions of the Work Incentive Program should be expanded. The administration had a bill in Congress this year, the Work and Training Opportunity Act, which was later withdrawn. That bill would have required all people on welfare who can work -- except mothers of young children -- to take part in a program that would first train people and then help them look for work.

This is a worthy approach, but not the whole answer. It is not enough to find work for people if work gives them less total income than they get in welfare payments or social services. Nor is it enough to find work for young people if their working penalizes their families severely by greatly reducing the amount of the family's welfare payment. A program to find work and train people for work must be combined with a time-limited program of health and social benefits. That sort of program would allow for the gradual independence of welfare recipients. The scary sudden independence that comes now when a person on welfare finds a job is something a good number of people tend to avoid, even if it means having to live off the small -- but sure and steady -- welfare check. For young people, that gradual weaning process could mean a special program that allows them to live at home for a time without unfairly reducing their family's welfare income.