Social attitudes usually reflect social conditions (not moral preferences)

It turns out that personal finance isn't so "personal."  Much of it has to do with prevailing attitudes toward financial conditions.  Bank of America CEO Kenneth Lewis recently worried in public [WSJ; behind firewall] about people who might walk away from their mortgages now their homes are worth less than their loan balance.

Calculated Risk puts up some scary numbers, which indicate the potentially seismic consequences of large-scale shifts in social attitudes. How scary?  How does TWO TRILLION strike you?

If every upside down homeowner resorted to "jingle mail" (mailing the keys to the lender), the losses for the lenders could be staggering. Assuming a 15% total price decline, and a 50% average loss per mortgage, the losses for lenders and investors would be about $1 trillion. Assuming a 30% price decline, the losses would be over $2 trillion.

Not every upside down homeowner will use jingle mail, but if prices drop 30%, the losses for the lenders and investors might well be over $1 trillion (far in excess of the $70 to $80 billion in losses reported so far).

There's a huge social component to personal ethics--much larger than we usually suppose.  Is walking away from your mortgage bad behavior?  Well, what if not only makes financial sense, but many people are doing it?  What if it were recommended?  Shame depends on the visibility of certain personal behavior in the eyes of a public, and there seems to be much less shame associated with cutting one's mortgage losses.  The big lesson (apart from the shame I hope the banks are feeling) is that personal character is developed in symbiosis with social conditions, not in spite of them.