Plato's Theory of Knowledge
What appears to be so to me is true for me, and what appears to be so to you is true for you. It follows that everyone’s perceptions are equally true. This of course is the extreme form of relativism that Protagoras claims when he asserts that man is the measure of all things in regards to truth. It seems that if all perceptions (e.g. judgments and beliefs) are equally true, there can be no room for expertise. But what is Protagoras to say of our natural inclination that such things as wisdom and the wise really do exist among individuals? If Protagoras’ relativism is to be accepted, he must explain how expertise is possible. Protagoras does not deny that some men are wiser than others, but he disagrees that some men are right while others are wrong. Though some men may appear to be wiser than others, it does not follow that their beliefs or judgments are truer than men who lack expertise in the given field; rather, and this is an important distinction that Protagoras makes, the judgments and beliefs of the wise are to be understood as being better (not truer) than those who lack expertise. For Protagoras, the wise man is the man “who can change the appearances—the man who in any case where bad things both appear and are for one of us, works a change and makes good things appear and be for him” (166d).
Before we attempt to unpack Protagoras’ definition of the wise, as stated above, I think it is important at this time that we give a brief historical account of what led Protagoras to speak of ‘better’ opinions and states. At one point in the Theatetus Socrates attempts to refute Protagoras by arguing somewhere between these lines: Let M be defined as the ‘man is the measure’ doctrine; 1) assuming M to be true, all perceptions must be true; 2) the majority of men think that M is false; 3) all of our judgments, including the judgment that M is false, must be true according to the very principles of M; 4) we can infer that M is false; hence a contradiction follows from 1) and 4) so M must be false. This argument is not a satisfactory response to Protagoras. All we would have to do is add the qualifiers ‘for so-and so’ and we get a different conclusion: 1) M appears true for Protagoras; 2) M appears false for everyone else; 3) It does not follow from 1) and 2) that M is false. We can only conclude that M is false for those who think it is false. One might be tempted to think that Protagoras can only defend his extreme relativism by employing qualifiers thus we should not take him very seriously since relativism is only true for x (in this case only for Protagoras) and not for everyone else. At this point it seems that we can simply ignore Protagoras since he is not of much help to us anymore. But what makes Protagorean relativism appealing is when Socrates switches to another line of reasoning, namely, he attempts to account for our common-sense beliefs of wisdom and expertise among individuals and gives a compelling defense on behalf of Protagoras. This is where the argument gets very interesting. Ultimately, if we are to refute Protagorean relativism I think our best approach is a discussion of what wisdom and expertise consist in, which brings us back to our original inquiry, that is, Protagoras’ (in behalf of Socrates) definition of wisdom and the wise. I will now proceed to give some examples to clarify the subtlety between ‘better’, ‘wiser’, and ‘truer’ states.
Are we to regard the sick Socrates as being less wise for perceiving the wine to be bitter than the healthy Socrates who perceives the wine to be sweet? Surely not. What Protagoras is trying to get us to see is that we should not regard the perceptions of the healthy Socrates as being wiser or truer than that of the sick Socrates, rather we may say that the healthy Socrates has better perceptions than the sick Socrates. By ‘better’ Protagoras simply means this: anyone who drinks wine prefers a sweet taste over a bitter one. So we...
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