Consumerism has boomed on debt. The huge profits of banks spring from massive borrowing too. In what are often referred to as "normal times", this is only sensible and right, according to capitalist logic. However, these are now abnormal times. They throw the culture of debt into high relief, perhaps affording us the opportunity to think about how debt shapes and makes us. "Be not a beggar by banqueting on borrowing", wrote the writer of Ecclesiasticus in the Hebrew bible. Has debt made us beggars, or at least undermined our power of self-possession?

Mark Vernon is the author of Wellbeing (Acumen, September 2008) - part of the Art of Living series he edits.

Also by Mark Vernon in openDemocracy:

"The politics of friendship" (29 December 2006)

"The life of the child: being friends, being good" (8 March 2007)

"Social networks: after privacy, beyond friendship" (24 October 2007)

"The bad faith of the secular age" (15 November 2007)At first glance, the opposite might seem to be the case. I recently overheard a conversation between a mother and her young daughter, of perhaps 4 years old. We were on the train, and the daughter was running through the toys she had with her. "My Narnia DVD", she said. "Oh, sorry darling. I think we forgot that", replied Mum. "Don't worry", retorted the child. "We can get it on the internet."

The little girl is growing up in an age where her desires can be fulfilled on demand, on credit. She may not yet know to purchase a second copy requires Mum to flex her plastic card. But maybe today - after the financial collapse in Wall Street - mother is teaching daughter a first lesson in personal finance: unlike the internet, credit is real, and right now is demanding to be paid back.

That the bubble of borrowing might be sagging under its own weight suggests itself in a different way, via a statistic. In the last six months, a staggering 55,000 mobile-phones were left in the back of London taxis. That's three per cab. What the report did not mention was how many owners bothered to recover their phones. After all, if you lose one there is - as long as you have a record of the numbers stored elsewhere - only a marginal inconvenience. For the whole logic of modern technology is that the gizmo itself doesn't matter: the valuable stuff, the data, is stored in virtual space. The device itself should cost nothing to replace, financed in part by credit. Might this philosophy of technology be another thing that changes as we rethink our relationship to debt? "Borrowing dulls the edge of husbandry", wrote Shakespeare.

The same stanza contains the injunction: "Neither a borrower, nor a lender be." The reason is that debt undermines relationships. This was something that the philosopher Jacques Derrida pondered when he wrote about gifts. In the modern world, he argued, it is not the giver who gives and the received who receives, but the converse: the giver receives and the receiver gives. This perverse logic arises because we think of gifts as putting the benefactors in our debt. If someone invites you for dinner, you owe them an invitation in return. Gift-giving in business is a means of purchasing special treatment.

That said, there are places in the world where gifts can still be given, in less commercially conscious environments. One is where I take my holidays, in south, rural France. Go when the farmer's hens are laying, and every morning there will a box of eggs at the gate. We say thank you, slightly embarrassed, wondering what we might give back. The farmer thinks precisely nothing of it.

Back in this world, Derrida concluded: "A gift is something you cannot be thankful for." What a depleted place it is.

Matt Barrett, when chief executive of Barclays Bank in 2003, made what became a notorious remark. "I don't borrow on credit cards because it is too expensive", he confessed. He was interpreted as implying that his own Barclaycard was a rip-off, and was derided in the press. Now, perhaps, we can hear his line in another sense. Are we learning that debt is not just financially but humanly too expensive?