In this exploration, I delve into Socrates’ argument for the tripartite soul, raising a potential objection to it. My analysis concludes that there might be a fundamental flaw in Socrates' reasoning.

This is the basic structure of Socrates’ argument:

[1] Nothing can do two opposite things at the same time (436b).

[2] People can have conflicting desires (439c).

[3] Thus there must be different parts of the soul (439d).

[4] These distinct parts can be classified based on their unique desires, with the part relating to knowledge and rationality being the rational part, the part relating to strong emotions being the spirited part, and the part relating to basic, primal desires being the appetitive part (439c-440a).

Now, I'll discuss these premises and their logical progression to [4], though it's worth noting that for the sake of this post, the specific classifications of different parts of the soul aren’t important, just the fact that the separation exists.

[1] is meant to be self-evident, with Socrates only offering a dispute to a semantic misunderstanding of the claim (If a person is standing and moving their head and arms at the same time, he isn’t both moving and not moving. One part of him isn’t moving, and two others are, so there is no contradiction.).

[2] is also meant to be self-evident. Clearly, people have conflicting desires. Any time someone is stuck choosing between doing and not doing something, or between two or more options, they're experiencing conflicting desires. Socrates brings up the example of thirst, with some people both wanting and not wanting to drink something. But I think a similar, clearer example is the internal battle that many have of wanting to maintain a healthy diet but also craving junk food. In this case, it is clear that a person can both want to eat something unhealthy because it tastes good, but also not want to eat it because of the long term negative effects it leaves.

[3] comes from [2] and [1], because if the soul (Socrates refers to the soul as being responsible for decision-making in humans) has conflicting desires, then it cannot be a single entity, otherwise, there would be a contradiction–it would be doing two conflicting things at the same time. Thus, the soul must be made of different parts, each with their own desires (439d).

This paves the way for [4], which offers a classification of these distinct parts. Using the analogy of a dieter from before, we can separate out two of them. The appetitive soul (related to primal desires) urges them to eat, while their rational part counsels restraint (439d). Socrates identifies another part–the spirited–using the tale of Leontius, who feels compelled to look at dead bodies, yet chastises himself angrily for doing so. This anger isn't attributable to the appetitive or rational part, but suggests the existence of a third, spirited part concerned with strong emotions (440a).

I will now turn to evaluating the argument. Both [1] and [2] make sense, and [4], though Socrates only uses examples to give weight to it, seems rational. But to me, it seems that [3] doesn’t necessarily follow from [1] and [2], and as such, I would like to consider a possible objection to it.

[3] assumes that conflicting desires imply multiple soul parts. Yet, our conflicts might be over different aspects of a decision, not the decision itself. For instance, a dieter's craving for unhealthy food doesn't mean they want and don't want the food; they may desire the taste but not the health effects.

Some may argue that we cannot dissect the object of our internal conflict into separate components since ultimately, our dilemma pertains to a single action. Even if we desire and reject unhealthy food for different reasons, we're still ultimately torn over the same action: eating. However, we might just hold varied opinions on different aspects of an action, not the action itself. This is exemplified by Socrates' perspective of the rational part of the mind, which encounters similar disagreements.

Consider someone solving a complex math problem, a task that engages only the rational part of the brain. After a while, this person might narrow down to two plausible answers. Each solution has its own set of justifications, yet there's no definitive mathematical proof for either. Eventually, after more thoughtful consideration, the individual chooses the option they believe is more likely to be correct. Although this person has differing opinions concerning different elements of the problem, they eventually weigh these factors against each other and opt for a single course of action—presenting the most likely correct answer. Likewise, the person choosing to eat an unhealthy snack might not be conflicted about the single action of eating but rather has differing opinions about the different consequences associated with that action, which they weigh against each other to reach their final decision, not requiring the soul to be split.

In conclusion, while exploring Socrates’ theory, I've presented a potential objection that challenges the logical flow of his argument. Since this objection seems irrefutable, it leads me to believe that Socrates’ argument for the tripartite soul might indeed be flawed.

1. Plato: The Republic, translated by G.R.F. Ferrari. (Cambridge Texts in the History of Political Thought.)