There’s a difference between predicting and knowing the future.
Predicting decreases uncertainty but does not eliminate it. We’ll call that level of certainty “knowing the future”. Predicting involves beliefs about the future state of the world and should be probabilistic, dealing in likelihoods of events, often describing a range of possible outomes.
I can make an excellent, accurate prediction about the card that will drawn from a deck. It will be one of the 52 cards in the deck.
Trivial? Not really. I’ve used my knowledge of the nature of card decks to constrain the possible range of outcomes to only those that are possible outcomes.
With more information about the particular deck I’d might be able to narrow the odds of various cards being drawn. For example armed with the exact order of cards in the deck and a historical dataset describing how often each card in each deck position is chosen, I could actually know which card is the single most likely to be drawn. Perhaps if we studied how people tend to draw cards we’d find that the center 25% got 60% of the draws, increasing the probability of those cards being selected over the top and bottom of the deck. Probably I’d be able to provide a list of the cards from most likely to be chosen through least likely.
Just because I know which card is most likely, it doesn’t mean that if the mostly likely card is not drawn in any particular trial that my prediction is wrong or inaccurate. The prediction only allowed me to strengthen my belief in some cards being drawn over other cards.
In selling any prediction service, If I only get one chance to test my ability to predict there’s no way to prove why I happened to be right or wrong. If my knowledge of the order of the deck and human behavior in selecting cards improved my ability to predict the card selected from 1 in 52 to 1 in 20, I’d be more than twice as good at picking the card to be drawn in advance, butits still overwhelming probable that my guess on any particular trial will be wrong.
It makes for a lousy magic trick but a very good way to make better decisions.
