I admit that I don't know who Tyler Cowen is, but millions (billions?) of people have drunk coffee daily for centuries and if there were ill effects in the same ballpark as opioids or tobacco by now we would certainly know?

A professor of economics has opinions on the health effects of an extremely common substance?

And I have opinions on nuclear energy - but neither of us are worth listening to outside our areas of expertise. Unless you can supply a reason I would bother listening to him as compared to an actual expert on the subject?

Why should I care what an economist's opinion is on coffee consumption?

> There is a big unknown.

Because some dude with no health or nutrition background said uninformed things, that he isn't qualified to have opinions about, on the internet? Come on, now.