Thinking rationally: The laws of thought approach The Greek philosopher Aristotle was one of the first to attempt to codify right thinking, that- SYLLOGISMS is, irrefutable reasoning processes. His syllogisms provided patterns for argument structures- that always yielded correct conclusions when given correct premises-for example, Socrates- is a man; all men are mortal; therefore, Socrates is mortal. These laws of thought were- LOGIC supposed to govern the operation of the mind; their study initiated the field called logic.- Logicians in the 19th century developed a precise notation for statements about all kinds- of things in the world and about the relations among them. (Contrast this with ordinary arithmetic- notation, which provides mainly for equality and inequality statements about numbers.) By 1965, programs existed that could, in principle, solve any solvable problem described in- LOGICIST logical n~tation.T~h e so-called logicist tradition within artificial intelligence hopes to build- on such programs to create intelligent systems. There are two main obstacles to this approach. First, it is not easy to take informal- knowledge and state it in the formal terms required by logical notation, particularly when the- knowledge is less than 100% certain. Second, there is a big difference between being able to- solve a problem in principle and doing so in practice. Even problems with just a few dozen- facts can exhaust the computational resources of any computer unless it has some guidance- as to which reasoning steps to try first. Although both of these obstacles apply to any attempt- to build computational reasoning systems, they appeared first in the logicist tradition. Acting rationally: The rational agent approach- AGENT An agent is just something that acts (agent comes from the Latin agere, to do). But computer- agents are expected to have other attributes that distinguish them from mere programs, such as operating under autonomous control, perceiving their environment, persisting over a- prolonged time period, adapting to change, and being capable of taking on anothers goals. A- RATIONALAGENT rational agent is one that acts so as to achieve the best outcome or, when there is uncertainty,- the best expected outcome.- In the laws of thought approach to AI, the emphasis was on correct inferences. Making- correct inferences is sometimes part of being a rational agent, because one way to act- rationally is to reason logically to the conclusion that a given action will achieve ones goals- and then to act on that conclusion. On the other hand, correct inference is not all of rationality, because there are often situations where there is no provably correct thing to do, yet- something must still be done. There are also ways of acting rationally that cannot be said to- involve inference. For example, recoiling from a hot stove is a reflex action that is usually- more successful than a slower action taken after careful deliberation.
Posted on: Sat, 28 Jun 2014 02:06:32 +0000