(Read more: Hedge funds play buy-and-hold, and lose)
That's not to say there isn't trouble brewing.
"Certainly risk tolerance has been increasing of late; high returns on risky assets have encouraged more of the same; and the markets are becoming more heated," Marks said. "The bottom line varies from sector to sector, but I have no doubt that markets are riskier than at any other time since the depths of the crisis in late 2008 (for credit) or early 2009 (for equities), and they are becoming more so."
While he's been a prominent voice for market skepticism over the past several years, Marks describes his current stance as merely "middling."
That's to say, he's in the market, but with a high degree of caution that echoes Warren Buffett's wisdom, "The less the prudence with which others conduct their affairs, the greater the prudence with which we should conduct our own affairs."
Those comments reflect a trend in which some notable bears—David Rosenberg, Hugh Hendry and others—have gone bullish, while bulls such as the equity team at Goldman Sachs have warned that stocks are approaching fully valued and are ripe for at least a garden-variety correction of 10 percent or so.
Citigroup strategist Tobias Levkovich has been cautious as well, warning about investors who simply follow trends and look for stocks that appear cheap.
(Read more: Market bears falling all over the place)
"Chasing performance tends to be a tough way to make a living and generally will not provide much of an early warning sign since the pattern needs to change before the behavior does," Levkovich said in a note. "Thus, measuring investor zeitgeist in a clear manner can beat an anecdotal sense of shifting sands."
For their part, retail investors have given the market a pretty clear thumbs-up, with fairly solid fund inflows and sentiment surveys showing clear optimism.
The most recent Investors Intelligence poll, for instance, shows bulls outnumbering bears 53.6 percent to 15.5 percent, the lowest level of bearishness in 2013 by a pretty wide margin.
Yet Marks said the signs of a 2007-style market implosion have not lined up.