For 2,000 years, the standard philosophical model of knowledge was that it could be defined as a Justified True belief.
This definition, which dates to Plato, was challenged by Edmund Gettier in one of the most influential works of philosophy published in the last century - a three page paper that produced two clear examples of Justified True beliefs that could not, in fact, be considered knowledge..
According to this way of thinking, we can know, for example, that we are human because [1] we believe ourselves to be human; [2] that Belief is Justified (others treat us as humans, not as dogs); and [3] the Belief is true.
For 2,000 years, the standard philosophical model of knowledge was that it could be defined as a Justified True belief
