The+Tripartite+Theory+of+Knowledge

(or 'Justified True Belief' - JTB)

For something to count as ‘knowledge’:


 * 1) It has to be justified - You have to have evidence to support your belief (a posteriori evidence - stuff you’ve experienced)
 * 2) You have to believe it is true
 * 3) It has to be true.

Simple as that.