mind & identity · new to this edition
do you really know?
three pages of philosophy that demolished a definition twenty-three centuries old.
Since Plato, knowledge was defined as <em>justified true belief</em>: you know something if it is true, you believe it, and you have good reason to. For 2,300 years that held. In 1963 Edmund Gettier published a paper barely three pages long and broke it. Judge these cases for yourself first.
does the farmer know there is a sheep in the field?
A farmer looks out across his field and sees, in the distance, a white woolly shape that looks exactly like a sheep. He forms the belief: there is a sheep in the field. He has excellent reason: it looks just like a sheep.
In fact the shape is a large white rock, deceptively sheep-like. But there is a sheep in the field, hidden behind a hillock, entirely out of view. So his belief is true, and justified.
further reading
- is justified true belief knowledge? wikipedia
- the analysis of knowledge stanford encyclopedia of philosophy