Turn on the TV any time these days, and you may hear someone sounding pretty certain about their view on the direction of inflation. That someone won’t be Howard Marks, veteran investor and billionaire co-founder of hedge fund Oaktree Capital. Driving the news: Marks admits he doesn’t know what’s next for inflation. And he says in a memo that investors should put little weight in forecasts about the economy because he’s "convinced the macro future isn’t knowable." Why it matters: The outlook for inflation is probably the most hotly debated topic in markets right now.