All those present are confounded by this discussion and ask Parmenides to go through the whole of his argument again, so as to explain his theories. After much hesitation Parmenides eventually agrees to do so. The group selects the youngest amongst them, Aristotle, to be his interlocutor.
Parmenides starts by declaring that, if an object is one, then one can not be many. Aristotle agrees with this hypothesis. Parmenides continues, saying that, if this is so, then there cannot be a part of the object nor can the object be whole, a conclusion that Aristotle questions. Parmenides then poses the query, if a part is a part of the whole, then what is a whole? He answers his own question. It would be something from which no part is missing. Therefore, in any case, the one thing would be composed of parts, both if it is whole and/or if it is composed of parts. Aristotle agrees with this definition. Parmenides then says that in both cases the one would be many rather than one. Aristotle also agrees with this definition. Parmenides adds that nonetheless, it must not be many but one. Therefore if one is to be one, then it can be neither whole nor have parts. If it does not have parts, then it cannot either have a beginning nor an end nor a middle, as these would be parts. Furthermore, a beginning and an end are limits, so as it can have neither, such an object would be unlimited. Therefore, it would be without shape, as it is neither round nor straight. This then also means that it would be nowhere.
In a similar manner Parmenides continues this line of argument over the supposition “if oneness is” for a considerable time. Parmenides attempts to sum up the argument by saying that “if oneness does not exist,” then things other than the one do exist. Others things will not be one and surely they will not be many unalike, since oneness would be present in things that are many. If none of these is one, he continues, they are all nothing, so they also cannot be many. If oneness is not present in others, they are neither many nor one. Neither are they one of many. They do not belong to any Form as they have no parts. So if oneness does not exist, none of the alike can be one or many, since without oneness it is impossible to conceive of many. Therefore, if oneness is not, otherness neither is, nor is conceived to be one or many. Hence they are neither alike nor unalike. To sum up, “if one does not exist, then nothing does.”
10 Philebus
Overview: Readers of this dialogue will find that they start in the middle of the discussion that Socrates is having with Philebus. As the reader enters, Philebus gives up his place in the ongoing discussion with Socrates to Protarchus. Later, when Socrates and Protarchus end the discussion, Protarchus remarks that they have not finished, and there are points he wants to discuss further at a later time. The modality where the thread of the dialogue is picked up in the middle is known as “in mediis rebus” or “in medias res.” The dialogue both begins and ends in the same fashion.
The subject of the discussion is how a human being can lead the best possible life that constitutes a good life. During this discussion, both Philebus and Protarchus choose the life of unbounded pleasure, whereas Socrates advocates a life of knowledge, reason, and intelligence. The three of them go on to discuss the nature of unity and plurality of both pleasures and knowledge. Socrates insists that there are different kinds of knowledge and different kinds of pleasures. They all agree that this plurality needs to be discussed, before they can discuss the nature of pleasure and of knowledge. They also discuss false pleasures and the comparison of freedom from pain as pleasure.
Finally, they agree that perhaps a combination of pleasure and knowledge might lead to the best chance for a happy life. Also included in their discussion is whether only pleasure or only knowledge would offer a second best choice for a happy life. They analyze this choice at considerable length, considering multiple possibilities. However, they are unable to come to a satisfactory conclusion. At this impasse Socrates suggests that they end the discussion. Protarchus refuses to stop, preferring that they continue to discuss a few more points that he has in mind. Thus, the dialogue for the reader ends in the middle of the discussion, that is the way it started. Perhaps Plato is leaving further conclusions up to the reader to think about and decide.
Though we know of no person by the name of Philebus in antiquity, the word Philebus in Greek means young lover. Perhaps Plato is trying to signify a life of pleasure by using this name.
In the company of a group of young men, Socrates discusses with one of them, Philebus, what constitutes a good life. In the middle of the discussion, Protarchus joins replacing Philebus. At this point Socrates sets out to inform Protarchus about the premise of their discussion. Socrates tells Protarchus that Philebus has argued that what is good for a person is to be pleased and delighted by pleasures and by whatever else goes with enjoyment. Socrates believes that knowledge, knowing, understanding, and what these traits engender are better than pleasure for both those now alive and for future generations. Protarchus agrees with Philebus and takes over further discussion of these divergent hypotheses.
Socrates comments that they will have to prove what will render life happy for all human beings. Both Philebus and Protarchus say that pleasures are what will make all humans happy, while, according to Socrates, knowledge is the key to happiness. Socrates brings up the possibility that there might be something in between pleasure and knowledge, and asks Philebus for his opinion. Philebus answers that for him pleasure always wins. Protarchus interrupts, stating that he has taken over from Philebus, and Philebus no longer has any say in the discussion. Philebus agrees and calls on the Goddess Aphrodite as the witness for his views.
Socrates says that, according to Philebus, though the Goddess is called Aphrodite her real name is Pleasure. He adds that he is always anxious about what name to use when referring to a God. He is willing to call Aphrodite by whatever name pleases her, but Pleasure is a complex title and must be considered carefully.
Socrates asks the group to consider that a debauched person gets pleasure from debauchery, while a sober minded person takes pleasure from sobriety. A fool may get pleasure from foolish opinions, whereas a wise man takes pleasure in his wisdom. He states that no sensible man can say that these different types of pleasures are alike. Protarchus agrees that pleasure can come from diverse and even opposite sources, but that such experiences are not contradictory to one another. How can pleasure from whatever source, not be simply unmitigated pleasure?
Socrates points out another anomaly. He says that a color is most like color. All colors are colors, but black is not only different from white but is opposite to white. In the same way different shapes are all very different. However, there is a type of unity of all things that are opposites. Likewise, some pleasures are contrary to other pleasures. Protarchus agrees with this interpretation, but he questions how it affects the argument in general? Socrates responds that the effect is present because all of these pleasures are called by different names. For example, all pleasant things are called good, but in some ways there are some good things that are bad. He then asks, if there is a common element that allows him to call all pleasures good? Protarchus does not accept that some pleasures are good while others are bad. Socrates tries to have him explain this statement by reiterating that some pleasures are unlike each other and some are opposites of each other. Protarchus maintains that this distinction does not apply in so far as they are all pleasures. Socrates concludes that this discussion has reached an unacceptable impasse. If he, for instance, says that wisdom, knowledge, and all similar things laid down at the beginning