Plato’s Theory of Soul and The Homunculus Problem

Plato’s theory of the soul and the Homunculus theory of human cognition are two distinct theories that both allude to the concept of a mind having smaller parts within it that are assigned to certain tasks and each responsible for the function of a certain cognitive capacity which, together, explain some aspect of the functioning of the whole Both theories use this cognitivist concept as an attempt to explain the complexity of the human mind and how the mind can function in multiple ways at once. However, the theories differ in a major way. Plato’s theory of the soul is a famous and controversial theory– which has been pondered since antiquity. The Homunculus theory is a more modern theory that we will juxtapose against Plato’s theory. However, the Homunculus theory entails a philosophical dilemma, which will soon be addressed, rupturing the credibility of the theory. Due to the similarities of the theories, the question remains, is Plato’s theory also vulnerable to this philosophical dilemma? To show that Plato is innocent of these charges, this essay will analyze both theories and the dilemma threatening them in order to ascertain a verdict.

Plato’s cognitivist theory of soul describes a soul with distinguished parts, each accounting for a human capacity, and together in their unique hierarchy they direct cognition. There are three in total including reason, spirit, and appetite, each is unique having its own goal. Reason speaks for justice of the soul, spirit aids and helps monitor reason to suppress appetite, while appetite lusts and is full of desires – ones which need to be controlled. In a just soul, appetite concedes to reason’s demand. These small parts produce overall cognition, on page 1074, 442 c-d, Plato defines what makes a man have reason, “we’ll call him wise because of that small part of himself that rules in him and makes those declarations.” Furthermore, Plato draws an important distinction between reason and appetite, in that they are genuine opposites, and uses this to explain why the mind must have multiple parts. A mind cannot be fully reasonable and fully appetitive the same time, “It is obvious… one thing but many” Plato says at 436B; just as an apple cannot be fully white and fully green at once. These are contradictory opposites.

On page 1068, 436 d, Plato gives the example of the spinning top, which in some non-contradictory sense both moves and does not move at the same time. To Plato, however, a contradiction would apply only applies if you look at the movement as a whole, once you assign movement to specific parts of the top it begins to make sense. For example, a point at the very center of the top will not move, however a point along its circumference will. Plato offers another example of when genuine contradiction occurs in the mind, on page 1070, 439 c, when he describes a thirsty person who does not want to drink. In this example, the person’s mind as a hole cannot both ask and forbid, say ‘yes’ and say ‘no’, at the same time, because they represent markers of two different agendas; therefore, the mutli-part brain serves an accurate explanation for the thirsty person’s neglect to drink. “What should we say… that bids?” was one of the questions Plato concerned himself with, and In this way the nature of Plato’s cognitivist theory begins to bloom, advocating for a cognitive system involving smaller entities inside the soul. A more modern theory, The Homunculus Theory, highlights a similar theme seen in Plato’s book 4 of the Republic, in regard to the concept of a person’s mind having smaller cognitive entities inside it, that help serve human capacities.

We will choose as our example a version of the Homunculus Theory discussed in D. Dennett. We can reject homunculus theories as ways to define cognitive action, such as sight, because of the danger of circular definitions but we might be able to accept in principle homunculus theories as explanations for how certain cognitive processes occur. Take as an example how the process of sight might occur: how do we, as a whole human being, see an object? According to a version of this theory, a visual homunculus in the brain sees an image of the object. However, the homunculus theory has a major weakness – it becomes subject to a philosophical dilemma First part: If the visual homunculus can see to the same degree as the whole person can, but we don’t think it is necessary to explain how it sees, then there should not be a need to explain how the whole person sees in the first place? Without a need for explanation the theory of a homunculus is void. Second part: The second part of the dilemma arises if there is need for an explanation: if everything that can see that also needs an explanation must have a visual Homunculus in it, and the visual homunculus itself can see, it too must have a visual homunculus in it, and another in that one, and so on, creating an infinite cycle of regress, never arising to a genuine explanation.

Plato’s theory of the soul shares resemblances to the Homunculus Theory, but the question remains, is it subject to the Homunculus Dilemma as well? If innocent, Plato’s theory has found a way to avoid the dilemma; however, a guilty verdict would corrupt Plato’s credibility and refute his theory. Some vulnerability to the Homunculus problem can seemingly be found in Book 4 of The Republic. On page 1073, 442 b-c, Plato argues: “And it is because of the spirited part, I suppose, that we call a single individual courageous.” Here Plato demonstrates a smaller cognitive part serving to explain the function of the individual’s overall cognitive action: the bravery of the whole individual is explained by the bravery of a part of the individual However, it fails to explain how the spirited part becomes courageous; but rather, we are merely told that it is so, thus threatening to set us off on the dilemma. In other instances as well, Plato finds himself threatened by the dilemma, for instance, in his juxtaposition of the soul and the state, he divides the state into three parts corresponding with those in the soul. In both cases a harmony among the three parts is necessary for universal justice. A city functions due to a joint effort of each social class, the auxiliaries, the nobles, and the working class, each with their own role and contribution.

“It necessarily follows that the individual is wise in the same way and in the same part of himself as the city,” Plato stated on page 1073, 441 c-d, indicating that there is a part of the soul responsible for wisdom, or reason, and city has an equivalent functioning part. This aspect of Plato’s theory is too vulnerable, because it again refers to the function of a smaller part entailing the function of the hole, without explanation of how the part itself functions. To avoid these charges, following Dennett, a Homunculus-Theory advocate could argue that the theory is valid as long as the smaller cognitive sub-division functions to a lesser degree than the whole or the one just above it. For example, the overall vision of an individual is composed of a three-dimensional experience, involving width, depth, and height.

Lets say for example, that the visual Homunculus receives two-dimensional stimuli, while another Homunculus comes along to interpret the stimuli, together allowing for the individual’s visual experience. In this way the sub-divisions on their own cannot create a clear message, yet are dependent on the other divisions. In this way the Homunculus problem can be easily dismissed: as long as the cognitive entity within is less sophisticated, it still makes sense to have sub-divisions. For example, a person can be rational if and only if a lesser cognitive part of the hole that has reason. To allow this premise we must conclude that the cognitive parts perform at a less sophisticated degree than reason itself, for example there could be a unique cognitive entity for rational calculation and rational inference, together producing the reason of the individual.

Although, as we have seen, there are indications of the Homunculus problem present in Plato’s work, unfortunately there are no indications of a solution to the dilemma employing Dennett’s hierarchy of increasingly simple-minded homunculi. Nevertheless, I am about to argue that Plato’s theory can escape the dilemma in another way. The nature of the dilemma begins with the attempt to explain how the Homunculus, or the inner part of the soul responsible for a certain cognitive action, is able to preform its duty. Plato gives no indication that he proposes to explain how the rational part of the soul is wise or the spirited part brave. But doesn’t this bring up the first part of the dilemma: if there is no need to explain why the smaller part is wise/brave, there should be no need to explain why the whole is wise/brave? To get around this Plato has an easy way out, simply rejecting this part of the dilemma altogether: even if there is no need to explain the sub-divisions behavior, because of the contrariety problem, there is a need to explain why the whole has that behavior.

The explanation is that there must be multiple parts to the mind, regardless of any other factors. For example, persons, as a whole, cannot both be rational and appetitive because they are contrary forces, each inhabiting a separate part of the mind. Plato demonstrates this on page 1067, 436 b, when he says “the same thing will not be willing to do, undergo opposites in the same part of itself, in relation to the same thing at the same time,” in other words, when it comes to opposites, it is impossible for them to come from the same source. With this, Plato concludes that multiple forces must be active in the soul to account for opposites occurring at once, and yet he is justified in taking there to be no need for further explanation how this occurs in the parts of the soul. This rejects the first part of the Homunculus Dilemma, thus freeing his theory of the soul from its grip.