Plato's Theory of the Metaphor of the Divided Line

In the process of discovering true knowledge, according to Plato, the human mind moves through four stages of development. At each stage, there is a parallel between the kind of object presented to the mind and the kind of thought these objects make possible. These objects and their parallel modes of understanding can be diagrammed as followed:

    OBJECTS                               MODES OF THOUGHTS
The God[FORMS]


In the diagram a vertical line is divided into four segments, each of which from the lowest to the highest represents a level of knowledge. Each level of knowledge imagining, belief, thinking, and knowledge has its own objects and its own method of knowing these. In the diagram the basic division is between knowledge, whose objects are in the intelligible world, and opinion, whose objects are in the visible world.


Imagining represents the lowest rang on the ladder formed by the divided line of knowledge. Imagining means the sense experience of appearances where in these appearance are taken as true reality. For example, a shadow, which can be mistaken as true reality. At this stage the mind does not know that it is a shadow or an image that it has confronted. If a person knew that it was a shadow, he would not be in the state of imagining.


The next level on the ascent of the divided line of knowledge is that of belief, which is the perception of actual objects. The level of belief is primarily the level of knowledge on which there occurs the recognition of  three dimensional visible objects. The visible objects depend upon their context for many of their characteristics. So, there is a degree of certainty in seeing things. But such certainty is not absolutely correct. Plato says that although actual things possess greater reality than their outlook, they do not by themselves give all the knowledge about them. Belief, which has its source in the perception by the sense of actual objects is insecure. It is not based upon abstracts truths or principles which are unchanging.


When a person moves from believing to thinking, he moves from the invisible world to intelligible world. In this level a person tries to find the explanation of every visible things. For example, when a mathematician sees a diagram of a triangle, he thinks about triangular. By using visible symbols, he provides a bridge from the visible to the intelligible world. Thinking is characterized not only by its treatment of visible objects as symbols, but also by reasoning from hypothesis. By a hypothesis, Plato means a truth, which is taken as self evident but which depends upon some higher truth. Here a hypothesis means a firm truth but one that is related to a larger context.


The mind is never satisfied as long as if must ask for a fuller explanation of things. Perfect knowledge requires that the mind should grasp the relation of everything to everything else. It represents the mind as completely released from sensible objects. At this level, the mind deals directly with the intelligible objects that have been abstracted from the actual objects. Here the mind uses no longer hypothesis. It is the highest level of knowledge which approached to the extend that the mind is able to move beyond the restrictions of hypothesis towards the unity of intelligible objects. Perfect intelligible therefore means the abstract view of reality which implies the unity of knowledge.