The Socratic influence on Plato is well known. Socratic matchless logic, flashing, irony, and sovereign intellect dominate the writings of Plato and Plato deserves no less credit than the influence of Socrates. There-was never a time when the Socratic was out of Plato's mind. Plato would never find himself complete without his master, Socrates. The fundamental idea of the Republic came to Plato in the form of his master's doctrine that virtue is knowledge. In most of Plato's writings, Socrates was seen almost everywhere, particularly in the Republic. 

Plato gave his teacher's doctrine virtue is knowledge a prime place in his philosophy. Like his teacher, Plato firmly believed that virtue can be attained through knowledge. He was convinced that human nature has four elements: reason, courage, temperance and justice. For Plato, the ruler, like a physician or a Navigator is an artist and to that extent, administration is an art.  Plato urged that the ruler should be one who knows the art, science and knowledge of administration.

  Theory of Forms or Ideas is at the centre of Plato's philosophy. All his other views, knowledge, psychology, ethics, and state can be understood in terms of this theory.  Following Socrates, Plato believed that knowledge is attainable and have two essential characteristics: one, knowledge is certain; two, that it is to be contracted with which is only appearance.  Plato's theory of Forms or Knowledge, or Idea is found in the Republic where he discussed the image of the divided line and the myth of the cave. 

 Plato made a distinction between two levels of awareness: opinion and knowledge. Claims or assertions about the physical or visible world are opinions. The higher level or awareness, on the other hand, is knowledge because there reason is involved. 

 The essential characteristics of Plato's theory of Forms include: (a) there is a difference between 'Form' or 'Idea'; 'Knowledge' and 'Appearance'; 'Actual', or 'Opinion' as there is difference between the ideally visible world and the physically visible world. (b) The form is the ultimate object of appearance. (c) The actual world can attain the ideal world. (d) Knowledge can replace opinion and is attainable. (e) The visible world is the shadow of the real world. (f) What appears to be is not the Form, but is a form of the Form. 

 Plato explained that there is a difference between things which are beautiful and what beauty is: former lies in the realm of opinion while the latter, the realm of knowledge. What is more important is Plato's insistence that the journey from 'appearances' to 'form' is possible through knowledge.