And if these algorithms, like the algorithms on Wall Street, just crashed one day and went awry, how would we know?

Financial markets responded by demanding much higher rates on the bonds of countries with high government debt ratios and banking systems weakened by excessive mortgage debt.

They told me that one of their residents, an old lady in her 90s, was seeing things, and they wondered if she'd gone bonkers or, because she was an old lady, whether she'd had a stroke, or whether she had Alzheimer's.