In Theaetetus, Socrates develops an account of what knowledge is which goes something like this. You have knowledge when you believe in something, that something is true and you have a justification for believing it. This is the classic account of what it means to know something.
I have a simpler description which fits better with how we think we know things today. You have knowledge when you believe in something and that something happens to be true.
I consider the addition of justification akin to a “no true Scotsman” fallacy.
Here is an example of a “no true Scotsman” fallacy.
Person A: “No Scotsman puts sugar on his porridge.”
Person B: “But my uncle Angus likes sugar with his porridge.”
Person A: “Ah yes, but no true Scotsman puts sugar on his porridge.”
To claim that my simple definition is “not true knowledge” follows the same pattern. A good justification will improve the credibility of the knowledge, but even without any justification, it is still knowledge.
Person A: “No one can know a fact without justification.”
Person B: “But my uncle Angus is Scottish and he knows that he is Scottish and says he just knows it without any justification .”
Person A: “Ah yes, but if it had been true knowledge, he would have a justification for it.”
I originally stated this 2012-12-10 in a philosophy discussion hosted by Coursera for the department of philosophy at EdinburghUniversity.