Sometimes our thinking about an object is conditioned by viewing the object from some particular perspective. A racing bicycle, for example, may be considered fast for a bicycle, but slow for a means of transportation. At other times, our thinking is conditioned by the context an object is in. A particular person, for example, may be happy when operating as a mountain hiker, yet grumpy when operating as an airplane traveler.
— Artificial Intelligence Second Edition
by Patrick Henry Winston