Lao Tzu

A great Chinese philosopher. His philosophy closely resembles the 'Vedanta' philosophy of India. He is said to have met Confucius who was his contemporary. During the last stage of his life he is said to have travelled West. Some think he came to India and met the Buddha. Lao Tzu's (also called Lao Zi) main work is the "Tao Te Ching" which is few thousand words in length and forms the crux of his philosophy if not for which work the Old One's greatness would not have been known. He shied away from public glory  as much as he could (this great work dispersed the clouds that covered the sun, Lao Tzu), throughout his life.

Socrates

What can be written about this great man. His wisdom is immortal. A great teacher of men. The Greek father of the Elenchus, a method of argument. A son of the Greek Gods. A guru (Indian for teacher) of such disciples of Plato. A visionary of the Utopian government. A fearless man and martyr. Socrates was supposed to be lost in reveries very much like Sri Ramakrishna Paramahamsa. No doubt all godly men are same. Socrates was arrainged by Meletus, Antyus and another of misguiding Athenian youth, worshipping false Gods and later poisoned as he failed to accept their other options (like stopping his discoursing, moving out of the city, paying a compensation). He humourously remarks that it is Athens which should rather pay him for his work. He was amazingly composed during his trial and death. There is just one more subtlety in Socrates. He says that death is not disaster at all (but as Epictetus would say, our opinion about it is).

Let the Lord Narayana bestow upon me as much wisdom as that of Socrates.

Socrates believed men to be immortal as they are not the body but the soul. That ignorance is the cause of all the world's ills. That Knowledge is the universal panacea for all ills. This, the knowledge of the soul and divinity, also called Wisdom. Socrates stressed on virtue as being the highest trait of man. He emphasised contentment and questioning to arrive at truths. He may rightly be called as the father of western philosophy. The soul takes birth again and again (like Sri Krishna says one discards his old clothes and puts on new ones, the soul reincarnates too). The soul knows all that is to be known and understood but it is masked, clouded by ignorance very much like the diamond being covered by the soil. It is just revealed to the soul, nothing is taught to it. In his argument with Meno he proves this by questioning a slave (who knows nothing about geometry, leave alone its axioms) and arriving at a geometrical concept accurately. Socrates arguments are an intellectual treat, pleasure for the soul.

Plato

A great philosopher worthy of the view of Emerson... "what is philosophy, Plato". If not for Plato, would we have known about Socrates. In other words wasn't Plato elected by the Gods to write about Socrates and his wisdom. Plato was of the royal family and was so devoted to Socrates that he could not bear to stay in Athens after Socrates's trial. Plato went around the world gathering wisdom and some say he might have been in India for some period of his life (The influence of Eastern wisdom, philosophy is conspicuous in his works)

Plato's greatest work is 'the Republic'. It is a fountain of Western Philosophy. It is said that all western philosophy are but footnotes to Plato.

Aristotle

A disciple of Plato. He was an analytical genius. But somehow to his great mind, the 'theory of forms' of Plato did not appeal. God knows if there is only one way of correct thinking. Aristotle was himself a believer in God and soul. He was a man of immaculate morality. His works include 'Politics', 'Ethics (Nicomachaen Ethics)', 'Metaphysics', 'Poetics' etc.  Aristotle was the tutor of Alexander the Great and was the father of the scientific method of enquiry.