Summary
Highlights
Philosophers have specific definitions for terms like 'know' and 'believe'. These definitions, while seemingly obvious, become more nuanced upon deeper consideration, raising questions about the nature of knowledge, truth, and justification.
An assertion is a linguistic act with a truth value (true, false, or indeterminate). A proposition is the underlying meaning or content of an assertion. The truth of a proposition depends on whether it corresponds to reality. Propositional attitude refers to a speaker's mental state towards a proposition.
Belief is defined as taking a propositional attitude of truth. One can hold false beliefs if their propositional attitude doesn't align with reality. Understanding belief is crucial for discussing knowledge.
Traditionally, knowledge is defined as a justified true belief. This means one must believe something, that belief must be true, and there must be legitimate evidence or justification supporting that belief. Justification can come from testimony or first-person observation.
American philosopher Edmund Gettier introduced 'Gettier cases' in the 1960s, which are situations where one can have a justified true belief but not actual knowledge. These cases demonstrate that simply being right by accident, even with justification, does not constitute knowledge.
One of Gettier's original cases involves Smith and Jones applying for a job, illustrating how Smith can have a justified true belief (the person who gets the job has 10 coins in their pocket) without truly knowing it, because his justification was flawed, and he stumbled into the correct answer by chance.
Roderick Chisholm's 'sheep in the field' example further highlights how a justified true belief can fail to be knowledge if the justification itself is based on a mistaken perception. Gettier cases have significantly impacted the philosophical debate surrounding the definition of knowledge, leading to ongoing discussions about its true nature.