Plato on Knowledge: Understanding Justified True Belief
The definition of knowledge has long plagued philosophers. Plato, founder of Western philosophy, tackled this very question around 400 B.C. According to Plato's philosophy, in order to have Knowledge, one must also have Justified True Belief. Each of these terms, for Plato, are necessary for the existence of knowledge.
Knowledge vs. Belief
In order to understand Plato's vision of knowledge, we must first make a concrete distinction between knowledge and belief. While its easy to say that opinion is not the same as knowledge, especially when it comes to opposing political views, this gets a bit trickier when it comes to belief. Essentially, a belief is akin to an opinion. It is one person's viewpoint that is not necessarily grounded in any facts. A person could believe that the earth revolves around the moon, or that the tooth fairy does indeed make a visit underneath every kid's pillow. The person could even believe that these are facts. Yet without a means to prove these "facts" as more than hypothesis, they remain opinion or belief, rather than knowledge.
Essentially beliefs can be defined as assumptions that we have formed about the world around us. Even a belief that happens to be true does not automatically become knowledge on the basis that it is fact. For example, a contestant on a game show, when asked, "Which president was taller, Abe Lincoln or Grover Cleveland?" guesses Lincoln. Every picture that the contestant has ever seen of Lincoln has showed him to be an extremely tall man. The contestant also cannot remember ever seeing a picture of Cleveland. It would be the opinion of the contestant that Lincoln was likely taller, yet he probably wouldn't bet a million dollars on it.
Because Lincoln actually was the tallest of all presidents, it would turn out that the contestant's opinion was correct, or true. However, just because he had a right opinion, did not mean that he knew that information. Thus even when the opinion or belief is correct, it cannot be considered actual knowledge.
Though belief and knowledge have been defined as two separate entities, it does not mean that in the Platonian view there can be one without the other. If I was to say that I know one plus one equals two, it would make no sense to say that I know this fact without believing it. Within Plato's formula, knowledge implies belief inherently.
Just as one must have a belief to have knowledge, it is also a requirement that it be a true belief. One cannot know something that is untrue. It would be impossible to find a person that could that they know that one plus one equals five, and there is not nor will ever be any sort of evidence that could support this statement as true.
The final component of knowledge, according to Plato, is justification. Without justification, says Plato, all we have is simply true opinion. Plato calls this justification a "tether," and uses an analogy of statues that will run away if not tied down. While a slightly esoteric example, what Plato is implying is that true opinion is fleeting. Belief is a state of mind, which can often be fickle and liable to change.
For example, let's say our game show contestant, who had seen many pictures of a tall Lincoln, suddenly remembered that in all those pictures Lincoln was wearing a hat. In light of this memory, the contestant might start to waver in his conviction that Lincoln was the taller president. Furthermore, if the contestant remembered an old college history professor once mentioning that Cleveland was a very tall man, he could even change his mind completely and opt for Cleveland as the safer answer.
Justification is the factual rationalization of true opinion, the thing that grounds it in reality. Without this justification, the true belief that Lincoln is the taller man is nothing more than a lucky guess or hypothesis. Similarly, if the contestant were to answer Cleveland, he would still only be relying on belief. What is lacking is the reliable information that places the entity of Lincoln as taller than the entity of Cleveland. This would be the contestant's rationale, the way that he could actually justify his belief that Lincoln was the taller man. If this justification were present, the contestant would likely then be willing to go ahead and bet the million on the question! The contestant would be able to say, "I know Lincoln is taller," because:
- The statement is correct (True).
- He believes that it is correct (Belief).
- He is justified in believing that it is correct (Justified).
According to Plato, our contestant would be the proud possessor of Knowledge.