Plato's definition of knowledge as justified true belief (JTB) has been a cornerstone of epistemology. This concept requires a proposition to be true, believed, and justified. However, the Gettier problem challenges this definition's sufficiency.

Edmund Gettier proposed scenarios where JTB fails to constitute knowledge. These cases involve true beliefs based on false premises or coincidence. The Gettier problem sparked debates about what additional conditions might be necessary for genuine knowledge.

The Traditional Definition of Knowledge

Components of Plato's knowledge definition

• Plato defines knowledge as justified true belief (JTB)
  • Proposition must be true reflects reality accurately
  • Person must believe accepts the proposition as true
  • Person must be justified has sufficient reasons or evidence for believing
• Each component is necessary for knowledge
  • Truth ensures the proposition aligns with the actual state of affairs (2+2=4)
  • Belief requires the person to sincerely accept the proposition (I believe the Earth is round)
  • Justification demands adequate grounds for believing, such as evidence or reasoning (I saw a globe showing the Earth's shape)

The Gettier Problem

Challenge of the Gettier problem

• Gettier problem, proposed by Edmund Gettier, challenges the sufficiency of JTB for knowledge
• Gettier cases are scenarios where a person has JTB but lacks knowledge
  • Typically involve forming a true belief based on false premises or coincidence (winning the lottery based on a dream)
• Gettier problem suggests JTB is not sufficient for knowledge
  • There may be additional conditions necessary beyond JTB (indestructibility of the belief)

Analysis of a Gettier case

• Consider the following Gettier case:
  • Smith and Jones applied for the same job
  • Smith has strong evidence Jones will get the job and has ten coins in his pocket
  • Smith forms justified belief: "The person who will get the job has ten coins in his pocket"
  • However, Smith unexpectedly gets the job instead of Jones
  • Coincidentally, Smith also has ten coins in his pocket, unaware of this fact
• In this case, Smith's belief is:
  • True: The person who got the job (Smith) does have ten coins in his pocket
  • Justified: Smith had strong evidence based on his knowledge about Jones
  • Believed: Smith genuinely believed the proposition
• However, it seems intuitive that Smith lacks knowledge in this case
  • His belief is only true by coincidence, not because of his justification (lucky guess)
• This Gettier case challenges Plato's JTB definition by showing it can be satisfied without knowledge

Responses to the Gettier Problem

Evaluation of Gettier problem solutions

• One proposed solution is the "no false lemmas" condition
  • States that JTB counts as knowledge only if not inferred from any false beliefs
  • In Smith and Jones case, Smith's belief was inferred from false belief that Jones would get the job
  • By ruling out beliefs inferred from false premises, aims to eliminate Gettier cases (faulty reasoning)
• Strengths of "no false lemmas" condition:
  • Successfully handles many Gettier cases, including Smith and Jones example
  • Preserves intuition that knowledge should not be based on false premises (house built on sand)
• Limitations of "no false lemmas" condition:
  • May be too strong and rule out cases of knowledge
    • Belief might be inferred from false premise but still qualify as knowledge if premise is irrelevant to truth of belief (Columbus believing he reached Asia)
  • May not handle all possible Gettier cases, as there could be other ways for JTB to fall short of knowledge (misinformation from trusted source)

Approaches to Knowledge

Epistemological perspectives

• Empiricism: emphasizes the role of sensory experience in acquiring knowledge
  • Knowledge primarily comes from observation and experimentation
• Rationalism: emphasizes the role of reason and innate ideas in acquiring knowledge
  • Some knowledge can be gained through pure reasoning, independent of experience
• Skepticism: questions the possibility of certain knowledge
  • Challenges the reliability of our senses and reasoning abilities
• Fallibilism: acknowledges that our beliefs and knowledge claims may be subject to error
  • Emphasizes the importance of ongoing inquiry and revision of beliefs

Types of knowledge

• A priori knowledge: knowledge that is independent of experience
  • Examples include mathematical truths and logical principles
• A posteriori knowledge: knowledge that is dependent on experience
  • Gained through observation and empirical investigation