Philosophy is said to be the mother of all sciences. The word "philosophy" means "love of wisdom". It deals with the three basic subjects, those are: the world, the life and things related to world & life. at the same time it asks the most prominent question of the universe, which is: "what is the ultimate reality of this world?"
Lets try to find out the answer from the discussions of the philosophers of different ages. Miletus Philosophers:
Western philosophy begins in the antiquity roughly at the same time when Western historiographers began to record history more or less systematically. Miletus was an ancient city on the western coast of anatolia. The group of philosophers who lived in this area are known as Miletus philosophers. They were a kind of materialist.
Thales:
Thales is considered as the father of philosophy. He was a mathematician rather than a philosopher, but in antiquity there was no differentiation between the natural sciences and philosophy.
Thales stated that the origin of all matter is water. Although this sounds a bit odd, there may be some truth in it. As we know today, the largest constituent of the universe is hydrogen, which makes two of the three atoms in water (H2O). The missing oxygen atom was added later when our planet formed. Scientists believe that liquid water is prerequisite to life, and we know with certainty that the first life forms flourished in the oceans, so water is indeed a primordial substance.
Anaximander:
Next comes the name of Anaximander. He was a Greek philosopher of Miletus, born 611-546 BC., and hence a younger contemporary of Thales and Pherecydes. We know very little of Anaximander's life. Most of the information on Anaximander comes from Aristotle and his pupil Theophrastus.
He preferred to represent it simply as a boundless something from which all things arise and to which they all return again. He was struck by a fact which dominated all subsequent physical theory among the Greeks, namely, that the world presents us with a series of opposites, of which the most primary are hot and cold, wet and dry. If we look at things from this point of view, it is more natural to speak of the opposites as being 'separated out' from a mass which is as yet undifferentiated than it is to make any one of the opposites the primary substance. Anaximander argued that Thales made the wet too important at the expense of the dry. According to Aristotle and Theophrastus, the first Greek philosophers were looking for the 'origin' or 'principle' (the Greek word 'arche' has both meanings) of all things.
Anaximander is said to have identified it with 'the Boundless' or 'the Unlimited' (Greek: 'apeiron', i.e. 'that which has no boundaries'). Already in ancient times, it is complained that Anaximander did not explain what he meant by 'the Boundless'. More recently, authors have disputed whether the Boundless should be interpreted as spatially or temporarily without limits, or perhaps as that which has no qualifications, or as that which is inexhaustible.
Anaximenes:
Anaximenes was an early Greek philosopher who lived in the 500's B.C.Like other philosophers of his time, he believed that there is a single substance underlying all things.
Unlike the others, Anaximenes believed that air being the principle of life, is the primary material, and becomes different things by condensation and rarefaction. He probably believed that people could more easily explain change in the world if the basic substance were something which could be regarded as the breath of the world.
Heraclitus:
Heraclitus was a pre Socratic Greek philosopher, a native of Euphas, the coast of Asia Minor.He was called "The Obscure," and the "Weeping Philosopher."
Heraclitus is famous for his doctrine of change being central to the universe, stated in his famous saying, "You cannot step twice into the same river." He believed in the unity of opposites, stating that "the path up and down is one and the same," existing things being characterized by pairs of contrary properties. His cryptic utterance that "all things come to be in accordance with this logos been the subject of numerous.The Sophist philosophers:
Protagoras:
Protagoras (ca. 490 420 BC) was a pre-Socratic Greek philosopher and is numbered as one of the sophists by Plato. In his dialogue Protagoras, Plato credits him with having invented the role of the professional sophist or teacher of virtue.
Socrates:
The most interesting and influential thinker in the 5th century Socrates, whose dedication to careful reasoning transformed the entire enterprise. Since he sought genuine knowledge rather than mere victory over an opponent, Socrates employed the same logical tricks developed by the Sophists to a new purpose, the pursuit of truth. Thus, his willingness to call everything into question and his determination to accept nothing less than an adequate account of the nature of things make him the first clear exponent of critical philosophy.
Plato:
The most illustrious student Socrates had in philosophy was Plato whose beautifully written dialogues not only offered an admiring account of the teachings of his master but also provided him with an opportunity to develop and express his own insightful philosophical views.
Plato was a more nearly systematic thinker than Socrates had been. He established his own school of philosophy, the Academy, during the 4th century and he did not hesitate to offer a generation of young Athenians the positive results of his brilliant reasoning. Although he shared Socrates's interest in ethical and social philosophy, Plato was much more concerned to establish his views on matters of metaphysics and epistomology. trying to discover the ultimate constituents of reality and the grounds for our knowledge of them.
Aristotle:
Aristotle ( (384 BC – 322 BC) was a Greek philosopher, a student of Plato and teacher of Alexander the great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, politics, government, ethics, biology, and zoology. Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures Western philosophy. Aristotle's writings constitute a first at creating a comprehensive system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics.
His idea consists of many ideas in his books Nicomachean Ethics, Politics etc.