Plato's Third Argument for the Just Soul
An analytical essay
Presented to Prof. Lori Alward
On this, the 5th of October, 1998
By Jared Earles

	Plato's third argument for the just soul in Book IX of The Republic raises the most interest. He argues that the synthesis of three criteria proves that pleasures of reason are more suited to the human soul. This implies the soul governed by reason would be far happier than the soul governed by appetite (a tyrannical soul). He first argues that reason is a pure pleasure. By this, he means that it is not mixed with pleasure or pain. He notes that all happiness based on appetite must be defined by a corresponding pain. For example, we appreciate a good smell more after experiencing a bad smell. Because reason does not rely on suffering, it supercedes appetite and spirit. Second, reason is an enduring pleasure. Appetite and spirit must be continually sought. There are always new pleasures to experience, new honors to win. Plato argues that because 
reason is an end in itself, it better suits the human nature. Finally, he explains that appetite and spirit enslave the soul. Aristocracy dissolves into a timocracy because of the continual pursuit of new honors and conquests. Hence, a tyrannical soul pursues appetite to a destructive end. Because of reason's purity, it liberates the soul to perceive the world, rather than enslaving it. 
Thus Plato's argument takes the form:
1.  Reason is a pure pleasure.
2.  Reason is an enduring pleasure.
3.  Reason is a liberating pleasure.
4.  Thus, pleasures of reason are more suited to human nature.

I will argue the invalidity of each of the first three principles, thus proving that reason is not inherently more suited to human nature than appetite or spirit.
	Against principle one, I argue that reason is just as reliant on pain and as similarly defined by its opposite both appetite and spirit. Plato explains that most of the people within society will not be qualified to be philosopher kings. The motivating factor is that they would not be reasonable. Given this, there is a dual existence of both reason and irrationality. The basis of The Republic is the proof of the pre-eminence of reason in a just soul. Furthermore, his second argument on justice in Book IX explains how a just soul knows all parts of the soul. Implicit in Plato's argument is that a reasonable soul chooses reason over irrationality. It should further be noted that Plato extensively argues that the absence of reason is painful to the soul. Thus, reason is defined by irrationality (a corresponding pain), making it mixed with suffering, just as both appetite and spirit.
	Philosopher kings continually seek more knowledge and understanding. Implied in Plato's definition of a philosopher king, is that they are lovers of truth and seekers of knowledge and understanding; moreover, there is subtle insinuation that a philosopher king would rather brood on the depth and purpose of existence, than govern a nation. This demonstrates that reason, too, is self-perpetuating. Once a soul values reason, it continually seeks greater understanding. Also, Plato does not appear to believe that there is a limit to one's knowledge. Given this, the drive for understanding is infinite. There are always new subjects to understand, new forms to comprehend. So, just as a tyrannical soul craves for pleasures of the body and spirited souls crave for honor, so too does a reasonable soul crave understanding.
	Finally, reason enslaves, not liberates, the soul. In Plato's hierarchy of knowledge, he underscores the idea that reason is the basis for all education. Given that philosopher kings are continually driven to further educate themselves, they must always exercise reason. Because Plato argues that reason is the sole proprietor of a just soul, all decisions that a just person makes 
must be based on reason alone. At the point a just soul chooses not to exercise reason, it has become enslaved to either spirit or appetite; thus, it is no longer just. From that, the necessary conclusion is that a just soul does not have a choice as to when to exercise reason (because it must always do so), just as a tyrannical soul has no choice when to exercise appetite. Thus, given 
the synthesis of my three arguments, Plato's conclusion that pleasures of reason are more suited to human nature is supported by invalid premises.
	The answer to these arguments is simple. Grant them all. A tyrannical soul is still enslaved by appetite, continually searching new pleasures, and often experiencing pain, both in order to validate them, and as a result of them. A just soul is enslaved by reason, continually searching understanding, and avoiding irrationality at all costs. Consequently, a tyrannical soul enslaves the best part of the soul to the worst part of the soul. Contrarily, a just soul enslaves the best part of the soul to its own betterment. What is the harm in this? None; therefore, a just soul which continually betters itself is far more desirable than a tyrannical soul which continually causes itself sorrow.