Definitions of Knowledge

• Plato's answer


  Knowledge is justified true belief
• Gettier cases

  Scenarios where an individual has a justified true belief but that is not knowledge
• Since Gettier's challenge, various alternative accounts of knowledge have been proposed
• Definitions of knowledge examined in A Level philosophy


  • Justified true belief (the tripartite definition)
  • JTB + No false lemmas
  • Reliabilism
  • Virtue epistemology
  • Infallibilism
• Types of knowledge


  • Ability: knowledge how
  • Acquaintance: knowledge of
  • Propositional: knowledge that
• Justified True Belief (the tripartite definition)

  Knowledge is true belief accompanied by a rational account
• Necessary and sufficient conditions

  Conditions that must be met for something to be defined as a term (e.g. 'bachelor' = 'unmarried man')
• 'Justified', 'true', and 'belief' are all necessary conditions for knowledge
• The tripartite definition of knowledge (justified true belief) is challenged by Gettier cases
• Gettier case 1


  Smith has a justified true belief that "the man who will get the job has 10 coins in his pocket", but this is not knowledge because it's just luck that led to him being correct
• Gettier case 2


  Smith has a justified true belief that "Either Jones owns a Ford or Brown is in Barcelona", but this is not knowledge because it's just luck that led to him being correct
• JTB + No false lemmas


  Knowledge is justified true belief where the belief is not inferred from anything false
• The JTB + No false lemmas definition avoids the problems of Gettier cases
• Fake barn county


  A situation where someone has a justified true belief that is not knowledge, because the belief is formed by looking at fake objects that happen to be true in one instance
• Reliabilism


  Knowledge is true belief caused by a reliable method that produces a high percentage of true beliefs
• Reliabilism allows for young children and animals to have knowledge
• According to the no false lemmas definition, Henry's belief is knowledge
• This shows that the no false lemmas definition must be false. Henry's belief is clearly not knowledge – he's just lucky in this instance
• Reliabilism


  James knows that P if: P is true, James believes that P, James's belief that P is caused by a reliable method
• Reliable method


  One that produces a high percentage of true beliefs
• If you form a belief through an unreliable method – for example by simply guessing or using a biased source – then it would not count as knowledge even if the resultant belief is true
• Advantage of reliabilism


  • It allows for young children and animals to have knowledge
  • Typically, we attribute knowledge to young children and animals
• Other definitions of knowledge imply that animals and young children can not have knowledge
• According to reliabilism, young children and animals are capable of possessing knowledge as they are capable of forming beliefs via reliable processes
• You can argue against reliabilism using the fake barn county argument: Henry's true belief that "there's a barn" is caused by a reliable process – his visual perception. Reliabilism would thus (incorrectly) say that Henry knows "there's a barn" even though his belief is only true as a result of luck
• Virtue epistemology


  Definitions of knowledge that link a belief to intellectual virtues
• Zagzebski argues that definitions of knowledge of the kind 'true belief + some third condition' will always fall victim to Gettier-style cases
• Zagzebski's definition of knowledge

  James knows that P if: James believes that P, James's belief that P arises from an act of intellectual virtue
• In Zagzebski's analysis, the 'truth' of the belief is implied by the idea of an act of intellectual virtues
• Sosa's virtue epistemology


  Knowledge has three properties: Accuracy (the belief is true), Adroitness (the believer is intellectually virtuous), Aptness (the belief is true because of the believer's intellectual virtues)
• Sosa's virtue epistemology could (correctly) say Henry's belief "there's a barn" in fake barn county would not qualify as knowledge – despite being true and formed by a reliable method – because it is not apt
• A potential criticism of virtue epistemology is that it appears to rule out the possibility of young children or babies possessing knowledge, despite the fact that they arguably can know many things
• Infallibilism


  For a belief to count as knowledge, it must be true and justified in such a way as to make it certain
• Infallibilism sets the bar way too high – barely anything can be known. Certainty is not a necessary condition of knowledge