Ok then. First off, whose reasoning should we use, since reasoning differs between people and constantly changes.
Second, let's use this example.
Let's say you (general you) are in a Texas hold-em tournament (don't personally think gambling is a good thing, just think that it is a good example for what I am trying to say) and you make it to the final heads-up. You and your opponent are about even in money and have been playing a while. You are dealt a 2-8 offsuit, (reason says fold right?) your opponent bets heavy since he has A-A. you decide to call anyways, the flop goes 2-2-2, giving you four of a kind, you go all in and end up winning the tournament and a couple million dollars.
I hope that example conveys why you cannot always use reason and logic to make the best decisions. While luck was involved, it something that happens in poker all the time (as well as real life), where you have a hand that should not be played and wind up winning the pot or even the tournament (an example, Doyle Brunson won the World Series of Poker two years in a row with a 10-2 hand (not a very good hand)). While reason is good to use and should definitely be taken into account when deciding on stuff, it is not always the best option.
May be a bad example, but I think that it kind of gets my point across.