Plato: Argument for the Tripartite soul

It the soul is tripartite, then it has three, not two, parts. Yes, people act in inconsistent ways because the three parts of the soul are sometimes in conflict with one another. I think that it is not a question of logical contradiction, but of conflict between, for example, the emotional part of the soul (or person) and the intellectual part of the soul (person).

Thank you, Kennethamy! I believe I understand that. So rather than have a unitary soul in conflict with itself (i.e. between spirit and reason), Plato reasoned that making it have three individual parts that could exist in harmony helped resolved such a potential conflict.

In The Republic it's important to keep reminding yourself that Plato is trying to draw comparisons from how societies operate to how human beings operate. I think that's important in understanding his logic behind the tri-partite theory.

It's been a while since I have read The Republic but from my understanding, Plato explores where conflicts arise in both men and states (societies). Plato likes to call the conflicts in question "injustice" and the dialogue is about how a just society would operate; then, how a just person would operate. Just like there are different institutions in society which do different things (the ruling class, the working class, etc) there are different institutions in the human being that do different things.

The logic is complicated, and difficult to put into any deductive or symbolic form. The law of non-contradiction doesn't come into play until Aristotle, but you're right in that it's close. The only thing is that Plato doesn't really logically show us why the soul is divided at all; it's done through allegory of the city-state. There are still similarities though, but the reason it's still not the law of non-contradiction is because of how it's spelled out for us.

Take this conflict for an example: "My Appetites (A) cause me to desire (D) to eat chocolate cake (CC), yet something causes me to reject the chocolate cake." In order for Plato to be using the law of non-contradiction, here's how he would have to argue:

1. My (A) cause me to (D) to eat the (CC).
2. I do not (D) to eat the (CC).
3. Since it cannot be the case that my (A) causes both (D) and ~(D),
CONCLUSION: something other than (A) must be the cause for me not [D] eating the (CC).

Now, this isn't to say this logic is invalid or unsound, and as you can see, the conclusion that there are multiple parts of human beings is still the same as Plato's. Additionally, Plato may well presuppose the law of non-contradiction, but it's not what he appeals to in his argument.

The reason for this is because Plato doesn't argue that we do not desire to eat the chocolate cake. Rather, we overcome that desire through the use of logic. I hope this illustration is clear in how this is not the law of non-contradiction. The difference is very subtle, yet important in the logical foundation of the theory.

Mostly you should turn your eye towards the allegory Plato is making. He's trying to find out what Justice is, both in the human being and in the city-state. Some people say that the three parts of the soul can be equated to the three other Platonic virtues: temperance, wisdom and courage. I'm not sure how well that works, but the discussion of the virtues is all over the place in The Republic.

Take a closer look at the comparison between the three types of classes (rulers, soldiers and workers) and the three parts of the soul (reason, spirit and appetite) to understand the logic behind the theory.

Aristotle doesn't really accept the theory as valid. But Aristotle doesn't really come into direct conflict with Plato right here but more on metaphysical forms and whatnot. The best way to look at whether or not Plato is valid is probably to look at the links he draws between what justice is for society and what justice is for an individual.

of course, this is all my own understanding / opinion, so take it for what it's worth!

eros (love) and thumos (passion) while the charioter which represents the intellect and rationality (nous)

In the Republic the three parts are called nous (intellect) thumos (passion) and epithumia (appetite).

I would think that the difference between these two allegories is duly noted by Plato scholars. In particular the question that looms most large to me is: Why is the eros of the Phaedrus traded in for the less noble epithumia of the Republic?

Thanks Deckard, you're absolutely right - Aristotle didn't have carte blanche on the law of non-contradiction; he's simply the one who coined the phrase and identified it's logical entailment. I can see how my post is misleading; primarily I was trying to show how in the tri-partite theory, Plato does not make a direct appeal to the law of non-contradiction.

It's been my experience, especially in the university setting, that the Plato/Aristotle line is very thin; using an Aristotelian term such as the law of non-contradiction in explaining a Platonic theory might get you into trouble - even if you're not wrong in doing so.

Deckard also brings up an interesting point - in Phaedrus Plato is much more focused on the dualism between the soul and the body. While there are three parts of the soul, they CAN be divided into two. I think this is where you are getting the dualism idea from. In Phaedrus Plato spells out the "lower" and the "higher" self - the higher being reason and the lower being passion and appetites. The lower parts are from our material body, while the higher part is something immaterial.

Deckard - I could be wrong, but I don't think either of the horses have names in Phaedrus. I am by no means an Ancient Greek scholar, but I believe Plato's primary concern with the horse/chariot example in Phaedrus is simply with the dualism of the soul, and doesn't really address the tri-partite theory found in the Republic. I think he's trying to talk about what happens when we let appetites govern us, and the horses represent good and bad appetites.

Since the Phaedrus dialogue overall is concerned with the idea of love (eros), I do not think Plato uses it to identify a part of the soul, but rather what governs parts of the soul. I think Plato keeps the same definition of eros that is given in the Symposium, as being a love with the aim of wisdom as it's goal. Eros has a place in logos, for example.

So in answer to your question, I would say there isn't really a conflict - epithumia is found in both books, and I believe it holds the same meaning. In fact, it is the whole aim of Socrates is to show Phaedrus why a life without epithumia is not the "good life" Phaedrus thinks it is. The upper and lower parts of the soul must work together, and eros can be found in both parts.

Aristotle stated the LNC as one of the "three laws of thought". The other two are, the law of the excluded middle, and the law of identity. Aristotle contended that they were the foundation of all thinking (or, at least, logical thinking).

Of course, Aristotle did not invent the notion that people cannot contradict themselves and be logical. John Locke wrote that God did not create Men with two legs, and then left it to Aristotle to make Men logical.

You are on the right track. All I can say is that Plato was...you know, platonic so doesn't that explain where he places his horses. But I don't know much about all this.

Actually, Plato was working with the Two-Element Metaphysics--it was never developed, but something I am doing. It divides the body of every living organism, and it is from the definiton of a thing. More found from me on the internet archive. The two elements are form and material difference, together they construct a thing. Thus you have three primitive categories of names. Names of things, names of that things forms, and names of that things material difference.

The tripartite soul is this, Emotion is our material difference. Logic, rationality, grammar, etc, is the form applied over emotion to construct a thing called us. So, we boot strap. The two horses are these two elements, combined, they are us at any time--the driver of the chariot. Rationality containing emotion, shaping it, produces human will.

In the Republic, Plato does not use "Aristotle's" non-contradiction which is about what we can say of something. This, he discusses in the Euthydemus. Plato's version in the Republic is non-contrariety -- what we cannot do or be done to at the same time in the same respect. With that, Plato's logical development is valid.

Hi there!
Please is there any one can help me explaining dialectic and the principle of non contradiction? (Plato's)