Plato's theory of knowledge

Plato was a very famous philosopher in ancient Greece. He was the disciple of Socrates and the master of Aristotle. Thus, Plato holds an important position in the history of philosophy and human civilization. One of the very important things that he dealt with in his book was the theory of knowledge. It was an important theory because people even in this modern age talk about this matter. Knowledge is a very important thing for us. Without knowledge, there is little difference between animals and human beings. 

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Plato thinks that knowledge is innate. In other words, human babies are born with the ability to learn knowledge. This is important because those who oppose this idea think that human babies are born with no innate skill of acquiring knowledge. They believe that human beings are taught and then they get knowledge. Another important thing that Plato talked about in his book The Republic was Analogy of the Divided Line (or Allegory of the Divided Line). 

In his book, Plato talks about this Divided line allegory in this way: 

Now take a line which has been cut into two unequal parts, and divide each of them again in the same proportion,[2] and suppose the two main divisions to answer, one to the visible and the other to the intelligible, and then compare the subdivisions in respect of their clearness and want of clearness, and you will find that the first section in the sphere of the visible consists of images. And by images I mean, in the first place, shadows, and in the second place, reflections in water and in solid, smooth and polished bodies and the like: Do you understand? 

Yes, I understand. 

Imagine, now, the other section, of which this is only the resemblance, to include the animals which we see, and everything that grows or is made. 

The visible world is what we can see. We believe in what we see, but we may also suffer from illusion and mistakenly believe the wrong thing as we may see the right thing in a wrong way because of illusion. Ordinary people may suffer from illusion more than educated people. On the other hand, there are some natural matters that are like universal truth and are part of the belief of every human being. Who can debate with the fact, The Sun rises in the east or Ocean has a lot of water. 

The intelligible world is related to abstract things. We can understand them by using our intelligence and common sense but cannot see them. For example, mathematical ideas and geometric ideas are like this. Most of the time, we cannot see or hear them but can feel them with our intelligence. Again, ordinary people struggle to grasp them. On the other hand, educated people with years of practice and education can understand them better. 

For this reason, philosophy is important to Plato. At the time of Plato, Philosophy was considered to be the highest form of knowledge. Science was not so advanced and science was considered to be a part of philosophy. So, the knowledge of philosophers was highest because it is pure. On the other hand, the knowledge of ordinary people is lowest as it is full of mistakes from illusion. 

Ordinary people take birth and then try little to acquire knowledge. So, for them, life is not so meaningful and significant. They are just bothered about their belief. They don’t care about truth and logic. They don’t know how to justify something. On the other, philosophers always aim for higher knowledge. They try to find truth and justification. The divided line does not divide knowledge only, but it divides human beings.