Aha! I think I've identified where our primary contention lies. First, as to the author overstating the case, I agree. If he really meant nobody is 100% certain of any given decision I can see where he is coming from, although I still wouldn't entirely agree. People who get off the freeway and drive home are not winging it. They are quite certain of the way (even if never guaranteed to survive the trip). This is just one of many instances which clearly does not agree with "none of us knows what we're doing". We clearly do a lot of the time.
Now, the place where I believe we are in discord is those instances when we are less certain we are making the right choice. If I walk up to a roulette table and choose black rather than red, and happen to win, I am certainly winging it and agree with you and the author entirely. However, I say the best chess player in the world would be able to tell you exactly why he (or she) made every move. They won't know with 100% certainty whether any given move is best, but they do know the logical mental progression taken to arrive at their choice, since they know strategy and likely outcomes. Similarly, Nobel Prize winning economists or physicists in large part know exactly what they are doing, for example, when driving home, and when working mathematical calculations. Our disagreement is over those rarer occasions when they are less certain of the correct choice. You seem to say it's the same as a 50% coin toss in these cases, and they are winging it. I firmly disagree. While they can't know with 100% certainty which choice is correct, they can know what is more likely correct (and why they believe so), and that is what separates them -- and Warren Buffet, and chess masters -- from everyone else.
So you would be OK with crediting our coin flipper if the coin had a 60/40 bias? It was his consistent skill in picking the 60% side that made him 1000x richer?
First, we have to look at the game. Let's say I'm one of the participants, and we are all told there are 1000 of us which will play a winner takes all coin toss game. There is one coin and each pair of players walks up to the coin, decides who will be the caller then watches for the result of the flip. We must all play until one person holds all the money. The first thing I'm going to do is casually head to the very back; that way I don't get eliminated until I reach the last person holding everyone's money, minus mine. At that point, if the coin was fair at 50/50 I would be happy to allow fate to decide whether I won very big, or lost my small stake. However, if the coin was biased at 60/40 favoring heads, and me being the astute observer I am noticed this tendency while awaiting my turn, when I reached the coin I would be sure to be the caller and firmly call heads. If I won, yes, I would give myself substantial credit for knowingly tipping the results in my favor.
The shorter answer to your question boils down to whether or not the winning caller used known information about the bias to his advantage. If he did, yes, he deserves some amount less than full credit -- fate will ultimately decide -- but more than zero credit, which would be in the case of a non-biased 50/50 choice. Also, I feel compelled to say I do believe Warren Buffet made the majority of his investment decisions on a mental certainty of far greater than 60% (unless the stake was quite small). One of the things about Warren Buffet's strategy is he buys for the long term, so, even if he's wrong in the short term, he won't sell. The company would practically have to go out of business for him to lose. The chance of that for companies he invests in is very slim.
Now, the place where I believe we are in discord is those instances when we are less certain we are making the right choice. If I walk up to a roulette table and choose black rather than red, and happen to win, I am certainly winging it and agree with you and the author entirely. However, I say the best chess player in the world would be able to tell you exactly why he (or she) made every move. They won't know with 100% certainty whether any given move is best, but they do know the logical mental progression taken to arrive at their choice, since they know strategy and likely outcomes. Similarly, Nobel Prize winning economists or physicists in large part know exactly what they are doing, for example, when driving home, and when working mathematical calculations. Our disagreement is over those rarer occasions when they are less certain of the correct choice. You seem to say it's the same as a 50% coin toss in these cases, and they are winging it. I firmly disagree. While they can't know with 100% certainty which choice is correct, they can know what is more likely correct (and why they believe so), and that is what separates them -- and Warren Buffet, and chess masters -- from everyone else.