|Belief, philosophy: attitude of considering a sentence to be true. Unlike religious faith belief is linked to the assessment of probabilities. See also belief, religious belief, propositional attitudes, intensions, probability, belief degrees._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
|Norvig I 450
Beliefs/agents/AI research/Norvig/Russell: [first, agents] have beliefs and can deduce new beliefs. Yet none of them has any knowledge about beliefs or about deduction. What we need is a model of the mental objects that are in someone’s head (or something’s knowledge base) and of the mental processes that manipulate those mental objects. >Ontology/AI research, >Objects of thought/Philosophical theories, >Objects of belief/Philosophical theories, >Propositional attitudes/Philosophical theories, >Modal Logic.
Norvig I 451
Modal logic/AI research/Russell/Norvig: Problem: Lois believes that Superman can fly but she doesn’t believe that Clark Kent can fly.
Solution: modal logic can use special modal operators for beliefs. This leads to the introduction of possible worlds. >Possible worlds/Philosophical theories, >Accessibility relation/Philosophical theories, >Barcan Formula/Philosophical theories.
Norvig I 453
Knowledge/agents: [when] we have a modal operator for knowledge, we can write axioms for it. First, we can say that agents are able to draw deductions; if an agent knows P and knows that P implies Q, then the agent knows Q. Furthermore, logical agents should be able to introspect on their own knowledge. If they know something, then they know that they know it.
Omniscience: one problem with the modal logic approach is that it assumes logical omniscience on the part of agents. That is, if an agent knows a set of axioms, then it knows all consequences of those axioms. This is on shaky ground even for the somewhat abstract notion of knowledge, but it seems even worse for belief, because belief has more connotation of referring to things that are physically represented in the agent, not just potentially derivable. >Omniscience/Philosophical theories._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
Stuart J. Russell
Artificial Intelligence: A Modern Approach Upper Saddle River, NJ 2010