Relevant alternatives theory(RAT) |
Relevant alternatives theory was primarily developed by Fred Dretske. It states that "knowing a true proposition one believes at a time requires being able to rule out relevant alternatives to that proposition at that time." One way that Dretske attempts to motivate RAT is with examples, such as the following:
You take your son to the zoo, see several zebras, and, when questioned by your son, tell him they are zebras. Do you know they are zebras? Well, most of us would have little hesitation saying that we did know this. We know what zebras look like, and, besides, this is the city zoo and the animals are in a pen clearly marked "Zebras." Yet, something's being a zebra implies that it is not a mule and, in particular, not a mule cleverly disguised by the zoo authorities to look like a zebra. Do you know that these animals are not mules cleverly disguised by the zoo authorities to look like zebras?
The relevant alternatives theorist claims that one does know that they are zebras, provided that any alternatives (e.g. the possibility of the zoo authorities cleverly disguising mules to look like zebras) are not relevant in the context in which knowledge is being attributed.
The important question, however, is: What makes an alternative relevant?(Wikipedia)
不変主義的RAT/文脈主義的RAT
"In short, at this early time, we already see a distinction between two ways of understanding Relevant Alternatives Theory. The first is a contextualist way, championed by Stine. The second is a non-contextualist way. It is just a fact about the knowledge relation that its holding depends upon relevant alternatives. This is the distinction between a contextualist versions of RAT and a “subject-sensitive” version. "(J.Stanley)
Fred Dretske(1970): non-contextualism
“Epistemic Operators”(1970)
“The Pragmatic Dimension of Knowledge”(1981)
Gail Stine(1976): contextualism
“Skepticism, Relevant Alternatives, and Deductive Closure”(1976)