I WENT to a gardening and DIY megastore the other day. As always, the approach to the car park was lined with Mexican day-labourers looking for work. Contractors in their pick-up trucks came hiring at the first hour, at the third, sixth, and ninth hours, and at the 11th hour.

I never run that gauntlet of hopeful men, aching to be hired for gardening, construction work, or anything else on offer, without thinking of the labourers in the vineyard (Matthew 20.16).

The labourers hired at the first hour complained: "These last have wrought but one hour, and thou hast made them equal unto us, which have borne the burden and heat of the day." The first-hour labourers got the pay they had accepted as a fair wage, but they could not stomach the fact that others were getting the same benefits without incurring the same hardships. They wanted things levelled down: the 11th-hour labourers should get less (or be made to work more).

Jobs are scarce in the United States. And most Americans who have those scarce jobs do not think, when they see others scrambling to get hired before their savings run out: "This could be me - let us set up social safety nets, provide unemployment benefits, and retraining." Instead, they reason: "I am bearing burdens in the heat of the day - working for a pittance behind this Walmart checkout; I am a cleaner, a casual labourer. It would be unfair for others to get comparable benefits without comparable misery."

President Reagan, in the 1980s, brought this to the attention of the general public. There were, he informed his fellow Americans, "welfare queens" who were popping out babies to get government benefits; and "strapping young bucks" (a Southern-dialect term for "young black males") buying groceries with government- issued food stamps, enjoying the gain without the pain.

Most Americans found this intolerable; so we replaced "welfare as we have known it" with TANF - temporary assistance to needy families, with a five-year lifetime cap on benefits. And we insisted that recipients pay through "workfare" - contrived drudge-work. The aim of these punitive programmes was to level down - to see to it that the 11th-hour workers did not do as well as the workers who did the whole shift. Fairness meant that the others should be made more miserable.

The levellers also targeted unionised government employees. Most working-class Americans regarded unions as a scam, run by lawyers to bankroll privileged employees, for whom they procured health insurance, pensions, and a living wage. These were benefits that most Americans did not get, and so most supported Republican-sponsored union-busting policies in order to make public employees as badly off as they were.

Occasionally, the Bible gets it right. Moses exhorts his followers: "You were aliens in Egypt, and were treated harshly (you know what it was like); so treat the aliens amongst you well." He could have said: "You were treated harshly; so treat the aliens badly in the interests of equality: level down." But he did not; and Jesus did not, either. He dismissed the complaints of the labourers first hired: "I will give unto this last, even as unto thee."

When people are badly off, and there are resources available to improve their lives without making others significantly worse off, we should, in fairness, redistribute those resources. But fairness is not an end in itself, and sacrificing well-being, levelling down to achieve greater equality, is not endorsed by Moses, Jesus, or the light of natural reason.

Dr Harriet Baber is Professor of Philosophy at the University of San Diego, USA.