“… If you wanted to go up or down a mountain, you had to look at it rather carefully. You wanted to reach the summit – but it would have been a mistake simply to look for an easy way up. As an experienced mountaineer, you first of all figure out where you must not go. You try to see possible avalanches, ice breaks, crevasses, and other fatal constraints. Only when you have, so to speak, blocked out the treacherous parts of the mountain, would you begin to plan your way up. At this point, you do make choices, but you make them within the space left between the mountains constraints. To “know” a mountain means to know where, on its slopes, you are relatively safe; it means to have learned the viable paths.”
Ernst von Glasersfeld, “Cybernetics and the Art of Living”