2 | “The just life is the happiest life.” Socrates on the proper constitution of the soul

[This is installment 2 in my Ethics 101 project.]

In my first installment, I posed the question: Why be moral?

Glaucon’s challenge to Socrates in Plato’s Republic suggests that this question is difficult to answer because there seem to be prima facie reasons to prefer acting immorally when it benefits us. The problem is that, intuitively, we think of morality as something intrinsically valuable – something that should carry weight in itself, regardless of whether or not it results in good consequences. Saying that one ought to be moral because, and only because, good things come from doing so seems to be a debasement of the idea of morality.

So anyways, this was the challenge posed by Glaucon at the beginning of Plato’s Republic. Hundreds of pages later (because Socrates has a tendency to ramble and get sidetracked), we finally get our answer.


As any good philosopher should, Socrates begins his response to Glaucon’s challenge by getting clear on the subject matter. Up until this point I have been using the terms “moral” and “just” somewhat synonymously, and indeed in everyday use we tend to associate one with the other. But Socrates has a very specific conception of justice: each part of a system playing its role and only its role, rather than taking over the role of another part for which it is less suited.

This can be applied generally, for example to a city: Justice in a city is achieved and maintained when everyone in that city knows their role and sticks to it; nobody is attempting to do anything they’re not supposed to do. Those who are best suited to rule are in positions of governmental power, those who are best suited to defend the city are soldiers, and so on for all the different roles a citizen may play.

This conception of justice can also be applied particularly, to individuals. Just like a city, an individual has different “parts” with different ideal functions. This is true in many senses – biologically, for example – but for Plato and Glaucon’s purposes the relevant sense is psychological.

According to Socrates, there are three main parts that make up our psychology (in the Republic he uses the word ‘soul‘): the rational part, the spirited part, and the appetitive part. The rational part of our psychology is in charge of weighing the options, making the best decisions for ourselves, and all that good stuff. Pretty intuitive. The appetitive part is also pretty intuitive: it’s the part of our psychology that deals with desire – whether that be hunger, lust, or whatever else one might crave. The spirited part of our psychology is probably the most difficult to grasp, but basically its job is to “help” the rational part. Oftentimes, what we rationally judge to be best for us conflicts with what our appetite craves. Our ‘spirit’ is supposed to help drive us in the direction of what’s rational.

Justice, then, when applied to the individual, means that each part of our psychology is playing the role that it ought to: the rational part is ultimately in charge of making decisions and the spirited part helps ensure this by keeping the appetitive part in check.

Conversely, injustice in an individual is when the parts of our psychology are out of whack; maybe the spirited part isn’t doing its job properly and our appetitive part is calling all the shots or something. I hope it’s immediately obvious to all of us how and why this could be a very bad thing.

So it turns out we do have reason to value justice as justice: we’d be pretty fucked without it! In some cases it may seem like not playing the part we’re supposed to (a law-abiding citizen, for example) can get us ahead, but Socrates thinks this is mistaken. If justice just is the parts of a system working together as they ought to, it’s pretty clear that we ought to want this wherever it can occur – whether it be in a city or in ourselves.


Reading this back to myself, I realize this is a bit anticlimactic. Honestly, I found Socrates’ answer to Glaucon’s challenge to be pretty unsatisfying too. In Plato’s defense, the book as a whole has a lot more to say – it was just irrelevant for my current purposes (i.e., the Bib Exam).

Next week I’ll discuss Hobbes’ response to the question “Why be moral?” from his work Leviathan.