I wish honorable gentlemen would have the fairness to give the entire context of what I did say, and not pick out detached words. (Cobden, Speeches 46, 1849, quoted intheOED) The importance of contextual reasoning is emphasized by various researchers in AI.

situations are the mathematical (albeit ontologically impoverished) counterparts of real situations, and unlike the latter, are amenable to symbolic manipulation. Given a real situation s, the set f' j s j= 'g is taken to be the corresponding abstract situation. (This set will be nonwellfounded when s is a circular situation. However, this need not concern us in this paper.) Let s be a given situation. Following the standard practice, we require the availability of some device for making reference to arbitrary objects of a given type 3 , viz. parameters. If x is a parameter and I is a finite set of infons (involving x), then there is a type [ x j s j= V '2I ']. This is the type of those objects to which x may be anchored 4 in s, so that all the conditions in I obtain. We refer to this process of obtaining a type---from a parameter x, a situation s, and a set I of infons---as type abstraction. Here x is the abstraction parameter and s is the `grounding' situation. In situati...