Socrates never left anything in written. His philosophical ideas can be reconstructed from the writings of Xenophon, the genius of his student Plato, or from works of Aristotle .
Which are these idease and what do they bring new to the world of the ancient philosophy? Being against philosophers who have dealt with the “world” in the physical meaning of it and wanted to know from what elements the world is made of, Socrates moved the center of philosophical research in from the external world to the inner world, from the cosmos to man. For more valuable than nature, for him it was the human nature.
“Know thyself “, the famous frontispiece maximum at Delphi.
Returning every eye on himself, man will find out what does and does not know, what can and can not do or be, this was Socrate’s thinking.
Against the Sophists, who looked like the same idea can be supported and fought with the same odds as there is no absolute truth, but that all knowledge is relative, that what is true for me and for others it is not, that what to me is true today may be tomorrow’s error, Socrates raises with all the energy and defend the absolute value of truth.
True knowledge, which questions the very essence of things is for him the most valuable good.But how do we come to the knowledge of the essences of things? Causing their notion. If we can determine which is the notion of working with it I find the very essence of it.
Socrates leave what is familiar and out of any doubt, from what is elemental and anyone knows how to attain the universal truth about it, the definition of that thing. In other words, he used the inductive process for knowing the essence of things.