Supporters of basic income come from many directions, and their best arguments are not all the same argument. This level presents them as their strongest defenders would.

Freedom

The Belgian philosopher Philippe Van Parijs, in Real Freedom for All (1995), argued that a just society should give each person the greatest real freedom to do whatever they might want to do. Formal freedom, the absence of legal barriers, is not enough; a person with no money is formally free to travel, study or start a business but cannot actually do so. Van Parijs argued that justice requires the highest sustainable basic income, because that gives the least advantaged the most real freedom. In an earlier paper, "Why Surfers Should Be Fed" (1991), he answered the objection that people who choose leisure deserve nothing: a state that rewards only those who prefer paid work is not neutral among ways of life.

A related argument comes from the republican tradition, which defines freedom as not being subject to anyone's arbitrary will. Writers in this tradition, such as Karl Widerquist, stress what they call the power to say no. The power to say no means being able to refuse an abusive job or relationship because survival does not depend on accepting it. A worker who can walk away gains bargaining power, they argue, and employers who must offer decent terms to attract staff will improve jobs. A spouse with an income of their own can leave a violent home.

Escaping the poverty trap

A practical argument concerns the design of means-tested benefits. When benefits shrink as earnings rise, the shrinkage acts like a tax. The effective marginal tax rate is the share of an extra dollar earned that is lost to taxes and reduced benefits combined. In some systems, poor households who earn a little more lose so much in housing aid, child care subsidies and food assistance that their effective rate tops 80 percent, and occasionally exceeds 100 percent at a "benefit cliff." A poverty trap is a situation in which earning more leaves a poor household little or no better off. Because a basic income is not withdrawn as earnings rise, it removes this part of the trap, though the taxes that fund it still apply.

Reaching people who are missed

Means-tested programs also miss many of the people they are meant to help. Applying takes time, documents and repeated proof of need, and many eligible people never claim. Non-take-up is the failure of eligible people to receive benefits they are entitled to. Studies in Europe often find rates of a third or more for some programs, owing to stigma, confusion and paperwork. A universal payment, defenders say, reaches everyone without the humiliation of proving poverty, and it costs less to administer because there is little eligibility to check.

Recognizing unpaid work

A feminist case starts from the vast amount of unpaid care that keeps households and economies running, most of it done by women. The political theorist Carole Pateman argued in 2004 that a basic income would recognize that contribution and loosen the link between full citizenship and paid employment. Feminist defenders argue that a basic income would give carers an independent income without tying it to a job. Others in the same tradition worry it might instead encourage women to stay home, an objection the next level takes up in another form.

Security in a changing economy

A newer argument is about risk. Gig work, irregular hours and possible job losses from automation leave many workers with incomes that rise and fall from month to month. A steady floor, its defenders argue, would act as insurance against those swings and let people retrain or take a chance on new work. Whatever the forecasts, supporters here make the more modest claim that a floor helps whichever way the forecasts turn out.

Finally, some defenders see a basic income as a share of a common inheritance, in the line of Paine and Spence. Land, natural resources, the stock of scientific knowledge and the data people generate were not created by any single owner, so everyone, they argue, deserves a dividend from them.

Worked example: Rosa's extra shift

Rosa is a single mother earning 1,500 dollars a month. Her employer offers her extra shifts worth 300 dollars a month. Under her current benefits, her housing aid would fall by 90 dollars, her child care subsidy by 120 dollars, and she would pay 45 dollars more in tax. Of the 300 dollars, she would keep 45, an effective marginal tax rate of 85 percent. She turns down the shifts, not from laziness but from arithmetic.

Now suppose her benefits were replaced by a basic income of the same value that did not shrink with earnings, funded by a flat tax of 30 percent. She would keep 210 dollars of the 300. Supporters say this is the core practical appeal. Critics reply that the 30 percent tax now falls on every worker's earnings, including millions of people who were never in a poverty trap, and that is where the next level begins.