Knowledge is generally thought to require justified true belief, even if justified true belief is not sufficient for knowledge, as Edmund Gettier famously argued. In the Meno, Plato demonstrates that true opinion is not equal to knowledge. However, Gettier holds a different opinion that justified opinion is not equal to knowledge, but it is necessary to knowledge. I support the Plato’s opinion that true opinion is not equal to knowledge, and that justified opinion is not necessary to having knowledge of something. In the Meno, Plato explores the relationship between knowledge and true opinion. For instance, Plato states, “As long as he has the right opinion about that of which the other has knowledge, he will not be a worse guide than the one who knows, as he has a true opinion, though not knowledge… … So true opinion is in no way a worse guide for correct action than knowledge” (Meno 97 b). In this quote, Plato explains that if a person has true opinion, it does not mean that the true opinion that the person has is knowledge.
In the following section of the Meno, Plato supports his opinion by showing that true opinion might escape from people’s mind but knowledge does not. For instance, “For true opinions, as long as they remain, are a fine thing and all they do is good, but they are not willing to remain long, and they escape from a man’s mind, so that they are not worth much until one ties them down by [giving] an account of the reason why… After they are tied down, in the first place they become knowledge, and then they remain in place” (Meno 98 a). Plato tries to demonstrate that true opinion won’t last for a long time, and it is just valid a short period of time. However, knowledge will exist for a long time, and won’t escape from man’s mind. True opinion cannot be tied down–if there is a thing which can be tied down and last for a long time it must be knowledge. Plato deals with the issue of true opinion versus knowledge in the second selection from the Meno. Meno raises roughly the objection that opinions that fall short of knowledge cannot be counted on to be true in the long run, “The man who has knowledge will aways succeed, whereas he who has true opinion will only succeed at times” (Meno 97 c).
But Socrates counters this response with a question: “Will he who has the right opinion not always succeed, as long as his opinion is right?” (Meno 97 c). In a jury case, we can say that the issue is not whether hearsay evidence is strong enough to warrant conviction, but rather whether true hearsay evidence, which will always issue in a proper verdict, is strong enough to warrant conviction. Furthermore, Meno asks Socrates why knowledge is prized, given that right opinion is always successful. The reason, Socrates responds, is that true opinion itself is not stable. Take the case of hearsay evidence. Sometimes it will produce true opinion and sometimes it will not. An eye-witness report, however, establishes a more direct link between the event in question and the opinion. Just like the previous theory, Socrates says that the missing element in mere right opinions is what “ties them down by [giving] an account of the reason why” (Meno 98 a). So knowledge differs from correct opinion in its being tied down. All Plato claims here is that knowledge is tied down and correct opinion is not.
Also, Plato did not bring up the jury case in the Meno. He may have thought that although an eye-witness account sufficiently constitutes knowledge, however, it is not sufficient. With respect to knowledge, there are two main problems with the world of the senses. The first is its instability. Things change from one kind of thing to another. Plato seems to have thought that this kind of impermanence makes the sensible world unsuitable for knowledge. The fundamental problem with the world of the senses is just that it is grasped by the senses, not by reason. Plato seemed to allow that true opinion could become knowledge if supplied with “an account of the reason why” (Meno 98a). But the ultimate reason why we will always be lodged in the world of the intellect. There is always room for error in the application of reason to any issue at hand. Only when reason itself is the object do we have knowledge, that is, do we have something that is tied down. Gettier’s cases are meant to challenge our understanding of propositional knowledge.
This is knowledge which is described by phrases of the form “knowledge that p,” with “p” being replaced by some indicative sentence (such as “Kangaroos have no wings”). It is knowledge of a truth or fact — knowledge of how the world is in whatever respect is being described by a given occurrence of “p”. Usually, when epistemologists talk simply of knowledge they are referring to propositional knowledge. It is a kind of knowledge which we attribute to ourselves routinely and fundamentally. Moreover, it is philosophically important to ask what, more fully, such knowledge is. Plato asked the questions prior to Gettier’s challenge, different persons would routinely have offered in reply some more or less detailed and precise version of the following generic three-part analysis of what it is for a person to have knowledge that p: Belief. The person believes that p. This belief might be more or less confident. And it might — but it need not — be manifested in the person’s speech, such as by her saying that p or by her saying that she believes that p.
All that is needed, strictly speaking, is for her belief to exist. Truth. The person’s belief that p needs to be true. If it is incorrect instead, then — no matter what else is good or useful about it — it is not knowledge. It would only be something else, something lesser. Admittedly, even when a belief is mistaken it can feel to the believer as if it is true. But in that circumstance the feeling would be mistaken; and so the belief would not be knowledge, no matter how much it might feel to the believer like knowledge. Justification. The person’s belief that p needs to be well supported, such as by being based upon some good evidence or reasoning, or perhaps some other kind of rational justification. Otherwise, the belief, even if it is true, may as well be a lucky guess. It would be correct without being knowledge. It would only be something else, something lesser.
Supposedly, each of those three conditions needs to be satisfied, if there is to be knowledge; and, equally, if all are satisfied together, the result is an instance of knowledge. In other words, the analysis presents what it regards as being three individually necessary, and jointly sufficient, kinds of condition for having an instance of knowledge that p. The analysis is generally called the justified-true-belief form of analysis of knowledge or JTB in short. For instance, your knowing that you are a person would be your believing that you are one, along with this belief’s being true and its resting upon much good evidence. That evidence will probably include such matters as your having been told that you are a person, your having reflected upon what it is to be a person, your seeing relevant similarities between yourself and other persons, and so on. It is important to bear in mind that JTB, as presented here, is a generic analysis.
It is intended to describe a general structuring which can absorb or generate comparatively specific analyses that might be suggested, either of all knowledge at once or of particular kinds of knowledge. It provides a basic outline — a form — of a theory. In practice, epistemologists would suggest further details, while respecting that general form. So, even when particular analyses suggested by particular philosophers at first glance seem different to JTB, these analyses can simply be more specific instances or versions of that more general form of theory. In Gettier’s opinion, is lucky to believe what is true on the basis of his evidence. For example, like Gettier’s case 1, “Jones is the man who will get the job, and Jones has ten coins in his pocket” (EDMUND L. GETTIER).
Jones is the man who will get the job. Jones is the man with ten coins in the pocket. It is easily to falsely believe that the man with ten coins will get the job. This is a justified opinion, not knowledge. More example, in lottery case if you hold a losing ticket you have a justified true belief that it will lose, the justification resting on your knowledge that it is very likely that any given ticket will lose, but many think you do not know that your ticket will lose. So having a justified true belief is not sufficient for knowledge, but it does seem necessary.
In my opinion, Plato’s theory is more close to the reality that true opinion in some ways is true but won’t last long. However, the knowledge can be tested by time. Compared to true opinion, it is the only thing that won’t be diminished by the long period of time. In conclusion, Plato demonstrates that the true opinion is not equal to knowledge. In some cases, true opinion might sound right. However, knowledge can never be replaced by true opinion. In contrast, Gettier thinks that justified opinion is necessary to the knowledge which I think is not because knowledge is must something which can tied down. Since, justified opinion cannot be tied down, therefore, it has no contribution to the knowledge.
1. Plato Meno (96d – 98b)
2. Is justified true belief knowledge? By Edmund L. Gettier