The history of philosophy is the study of philosophical ideas and concepts through time. Issues specifically related to history of philosophy might include (but are not limited to): How can changes in philosophy be accounted for historically? What drives the development of thought in its historical context? To what degree can philosophical texts from prior historical eras even be understood today?

All cultures — be they prehistoric, ancient, medieval, or modern; Eastern, Western, religious or secular — have had their own unique schools of philosophy, arrived at through both inheritance and through independent discovery. Such theories have grown from different premises and approaches, examples of which include (but are not limited to) rationalism (theories arrived at through logic), empiricism (theories arrived at through observation), and even through leaps of faith, hope and inheritance (such as the supernaturalist philosophies and religions).

History of philosophy seeks to catalogue and classify such development. The goal is to understand the development of philosophical ideas through time.

Western philosophy

Western philosophy has a long history, conventionally divided into four large eras - the Ancient, Medieval, Modern, and Contemporary. The Ancient era runs through the fall of Rome and includes the Greek philosophers such as Plato and Aristotle. The Medieval period runs until roughly the late 1400s and the Renaissance. The "Modern" is a word with more varied use, which includes everything from Post-Medieval through the specific period up to the 20th century. Contemporary philosophy encompasses the philosophical developments of the 20th century up to the present day.

Ancient philosophy

Further information: Ancient philosophy

Western Philosophy is generally said to begin in the Greek cities of western Asia Minor (Ionia) with Thales of Miletus, who was active around 585 B.C. and left us the opaque dictum, "all is water." His most noted students were Anaximenes of Miletus ("all is air") and Anaximander (all is apeiron).

Other thinkers and schools appeared throughout Greece over the next couple of centuries. Among the most important were Heraclitus ("all is fire", all is chaotic and transitory), Anaxagoras (reality is so ordered that it must be in all respects governed by mind), the Pluralists and Atomists (the world is composite of innumerable interacting parts), the Eleatics Parmenides and Zeno (all is One and change is impossible), the Sophists (became known, perhaps unjustly, for claiming that truth was no more than opinion and for teaching people to argue fallaciously to prove whatever conclusions they wished). This whole movement gradually became more concentrated in Athens, which had become the dominant city-state in Greece.

There is considerable discussion about why Athenian culture encouraged philosophy, but a popular theory says that it occurred because Athens had a direct democracy. It is known from Plato's writings that many sophists maintained schools of debate, were respected members of society, and were well paid by their students. Orators influenced Athenian history, possibly even causing its failure (See Battle of Lade). Another theory explains the birth of philosophical debate in Athens with the presence of a slave labor workforce which performed the necessary functions that would otherwise have consumed the time of the free male citizenry. Freed from working in the fields or other manual economic activities, they were able to participate in the assemblies of Athens and spend long periods in discussions on popular philosophical questions. Students of Sophists needed to acquire the skills of oration in order to influence the Athenian Assembly and thereby increase respect and wealth. In response, the subjects and methods of debate became highly developed by the Sophists.

The key figure in transforming Greek philosophy into a unified and continuous project - the one still being pursued today - is Socrates, who studied under several Sophists. It is said that following a visit to the Oracle of Delphi he spent much of his life questioning anyone in Athens who would engage him, in order to disprove the oracular prophecy that there would be no man wiser than Socrates. Through these live dialogues, he examined common but critical concepts that lacked clear or concrete definitions, such as beauty and truth, and the virtues of piety, wisdom, temperance, courage, and justice. Socrates' awareness of his own ignorance allowed him to discover his errors as well as the errors of those who claimed knowledge based upon falsifiable or unclear precepts and beliefs. He wrote nothing, but inspired many disciples, including many sons of prominent Athenian citizens (including Plato), which led to his trial and execution in 399 B.C. on the charge that his philosophy and sophistry were undermining the youth, piety, and moral fiber of the city. He was offered a chance to flee from his fate but chose to remain in Athens, abide by his principles, and drink the poison hemlock.

Socrates' most important student was Plato, who founded the Academy of Athens and wrote a number of dialogues, which applied the Socratic method of inquiry to examine philosophical problems. Some central ideas of Plato's dialogues are the Theory of Forms, i.e., that the mind is imbued with an innate capacity to understand and contemplate concepts from a higher order preeminent world, concepts more real, permanent, and universal than or representative of the things of this world , which are only changing and temporal; the idea of the immortal soul being superior to the body; the idea of evil as simple ignorance of truth; that true knowledge leads to true virtue; that art is subordinate to moral purpose; and that the society of the city-state should be governed by a merit class of propertyless philosopher kings, with no permanent wives or paternity rights over their children, and be protected by an athletically gifted, honorable, duty bound military class. In the later dialogues Socrates figures less prominently, but Plato had previously woven his own thoughts into some of Socrates' words. Interestingly, in his most famous work, The Republic , Plato critiques democracy, condemns tyranny, and proposes a three tiered merit based structure of society, with workers, guardians and philosophers, in an equal relationship, where no innocents would ever be put to death again, citing the philosophers' relentless love of truth and knowledge of the forms or ideals, concern for general welfare and lack of propertied interest as causes for their being suited to govern.

Plato's most outstanding student was Aristotle, perhaps the first truly systematic philosopher. Aristotelian logic was the first type of logic to attempt to categorize every valid syllogism. A syllogism is a form of argument that is guaranteed to be accepted, because it is known (by all educated persons) to be valid. A crucial assumption in Aristotelian logic is that it has to be about real objects. Two of Aristotle's syllogisms are invalid to modern eyes. For example, "All A are B. All A are C. Therefore, some B are C." This syllogism fails if set A is empty, but there are real members of set B. In Aristotle's syllogistic logic you could say this, because his logic should only be used for things that really exist ("no empty classes")

The application of Aristotelian logic is preceded by having the student memorize a rather large set of syllogisms. The memorization proceeded from diagrams, or learning a key sentence, with the first letter of each word reminding the student of the names of the syllogisms.

Each syllogism had a name, for example: "Modus Ponens" had the form of "If A is true, then B is true. A is true, therefore B is true."

Most university students of logic memorized Aristotle's 19 syllogisms of two subjects, permitting them to validly connect a subject and object. A few geniuses developed systems with three subjects, or described a way of elaborating the rules of three subjects.

Medieval philosophy

Further information: Medieval philosophy

Medieval philosophy was greatly concerned with the nature of God, and the application of Aristotle's logic and thought to every area of life. One continuing interest in this time was to prove the existence of God, through logic alone, if possible. The point of this exercise was not so much to justify belief in God, since in the view of medieval Christianity this was self-evident, but to make classical philosophy, with its extra-biblical pagan origins, respectable in a Christian context.

One early effort was the cosmological argument, conventionally attributed to Thomas Aquinas. The argument roughly is that everything that exists has a cause. But since there could not be an infinite chain of causes back into the past, there must have been an uncaused "first cause." This is God. Aquinas also adapted this argument to prove the goodness of God. Everything has some goodness, and the cause of each thing is better than the thing caused. Therefore, the first cause is the best possible thing. Similar arguments were used to prove God's power and uniqueness.

Another important argument for proof of the existence of God was the ontological argument, advanced by St. Anselm. Basically, it says that God has all possible good features. Existence is good, and therefore God has it, and therefore exists. This argument has been used in different forms by philosophers from Descartes forward.

As well as Aquinas,

HISTORY OF WESTERN PHILOSOPHY FROM 1492 TO 1776

Site is intended for anyone interested in the stars and marvels of the history of philosophy from the 16th through the 18th century.

...

Journal of the History of Philosophy

Quarterly journal devoted to the history of Western Philosophy, broadly conceived. Associated with the Duke University Philosophy Department. Edited by Tad M. Schmalz, and ...

...

History and Philosophy of Biology Resources

Directory devoted to the field by Roberta L. Millstein includes references works, societies, weblogs, journals, historians and philosophers of biology.

...

History of Philosophy

A very large, diverse collection of essays addressing many philosophical, historical, scientific, religious, economic, legal, and political issues. Edited by Kelley L. Ross.

...

History of philosophy - Wikipedia, the free encyclopedia

The history of philosophy is the study of philosophical ideas and concepts through time. Issues specifically related to history of philosophy might include (but are not limited to ...

...

TPM: The Philosophers’ Magazine | Rewriting history

Chris Lawn laments our insensitivity to historical context. There is an orthodox view in the discipline of philosophy, prevalent in the Anglophone world, and it goes something like ...

...

History and Philosophy of Biology. Department of Sociology and ...

History and Philosophy of Biology at Exeter. The History and Philosophy of Biology has emerged in recent years as one of the most dynamic and challenging sub-fields within history ...

...

History of Philosophy

A survey of the history of Western philosophy. ... History of Western Philosophy The pages of this section offer a narrative survey of the historical development of Western ...

...

History of Western Philosophy (Russell) - Wikipedia, the free ...

A History of Western Philosophy And Its Connection with Political and Social Circumstances from the Earliest Times to the Present Day (1945) by the philosopher Bertrand Russell is ...

...

A History of Greek Philosophy - 1

A Short History of Greek Philosophy, by John Marshall - with notes and study links by Elpenor

...