Why a legendary Wall Street permabear is suddenly sounding more upbeat

ANGELA WEISS / AFP via Getty Images

• John Hussman, an enduringly bearish voice on Wall Street, is adjusting his investment calculus.
• Hussman said the market's best days increasingly come amid "dangerous" conditions.
• Still, the longtime market bear remains cautious with valuations near all-time highs.

It's a rare day when John Hussman, the legendary permabear who called the 2000 and 2008 crashes, expresses a degree of optimism about stocks.

One of those days came this week...