Introduction

ARISTOTLE
Aristotle was Plato's greatest student. One of his big contributions to philosophy was the theory of the four kinds of causes. Aristotle's ideal state would be ruled by the virtuous citizens. Aristotle thinks that a state is an association for allowing each citizen to live well. What was Aristotle's notion of friendship? It was broader than our modern notion of friendship. It was closer to the idea of people helping each other be virtuous.
Aristotle thought the state had a duty to morally improve its citizens. Modern political theorists do not agree.
Aristotle didn't think that the state should be barred from religion and censorship.
Aristotle's ethical theory was centered on the question of what kind of life to live. It was not concerned with discovering what actions are right.

Aristotle (Greek: Ἀριστοτέλης [aristotélɛːs], Aristotélēs) (384 BC – 322 BC)[1] was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music,logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology. Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. Aristotle's writings were the first to create a comprehensive system of Western philosophy, encompassing morality, aesthetics, logic, science, politics, and metaphysics.
Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by Newtonian physics. In the zoological sciences, some of his observations were confirmed to be accurate only in the 19th century. His works contain the earliest known formal study of logic, which was incorporated in the late 19th century into modern formal logic.
In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially the scholastic tradition of the Catholic Church. Aristotle was well known among medieval Muslim intellectuals and revered as المعلم الأول - "The First Teacher".
His ethics, though always influential, gained renewed interest with the modern advent of virtue ethics. All aspects of Aristotle's philosophy continue to be the object of active academic study today. Though Aristotle wrote many elegant treatises and dialogues (Cicero described his literary style as "a river of gold"),[2] it is thought that the majority of his writings are now lost and only about one-third of the original works have survived.[
Logic
Aristotle portrayed in the 1493Nuremberg Chronicle as a scholar of the 15th century A.D.
Main article: Term logic
With the Prior Analytics, Aristotle is credited with the earliest study of formal logic, and his conception of it was the dominant form of Western logic until 19th century advances in mathematical logic. Kant stated in the Critique of Pure Reason that Aristotle's theory of logic completely accounted for the core of deductive inference.
History
Aristotle "says that 'on the subject of reasoning' he 'had nothing else on an earlier date to speak of'" However, Plato reports that syntax was devised before him, by Prodicus of Ceos, who was concerned by the correct use of words. Logic seems to have emerged from dialectics; the earlier philosophers made frequent use of concepts like reductio ad absurdum in their discussions, but never truly understood the logical implications. Even Plato had difficulties with logic; although he had a reasonable conception of a deductive system, he could never actually construct one and relied instead on his dialectic. Plato believed that deduction would simply follow from premises, hence he focused on maintaining solid premises so that the conclusion would logically follow. Consequently, Plato realized that a method for obtaining conclusions would be most beneficial. He never succeeded in devising such a method, but his best attempt was published in his book Sophist, where he introduced his division method.
Analytics and the Organon
Main article: Organon
What we today call Aristotelian logic, Aristotle himself would have labeled "analytics". The term "logic" he reserved to mean dialectics. Most of Aristotle's work is probably not in its original form, since it was most likely edited by students and later lecturers. The logical works of Aristotle were compiled into six books in about the early 1st century AD:
Categories
On Interpretation
Prior Analytics
Posterior Analytics
Topics
On Sophistical Refutations
The order of the books (or the teachings from which they are composed) is not certain, but this list was derived from analysis of Aristotle's writings. It goes from the basics, the analysis of simple terms in the Categories, the analysis of propositions and their elementary relations in On Interpretation, to the study of more complex forms, namely, syllogisms (in the Analytics) and dialectics (in the Topics and Sophistical Refutations). The first three treatises form the core of the logical theory stricto sensu: the grammar of the language of logic and the correct rules of reasoning. There is one volume of Aristotle's concerning logic not found in the Organon, namely the fourth book of Metaphysics.[17]
Aristotle's scientific method

Plato (left) and Aristotle (right), a detail ofThe School of Athens, a fresco by Raphael. Aristotle gestures to the earth, representing his belief in knowledge through empirical observation and experience, while holding a copy of his Nicomachean Ethics in his hand, whilst Plato gestures to the heavens, representing his belief in The Forms.
"Aristotle" by Francesco Hayez (1791–1882)
Like his teacher Plato, Aristotle's philosophy aims at the universal. Aristotle, however, finds the universal in particular things, which he calls the essence of things while Plato finds that the universal exists apart from particular things, and is related to them as their prototype or exemplar. For Aristotle, therefore, philosophic method implies the ascent from the study of particular phenomena to the knowledge of essences, while for Plato philosophic method means the descent from a knowledge of universal Forms (or ideas) to a contemplation of particular imitations of these. For Aristotle, "form" still refers to the unconditional basis of phenomena but is "instantiated" in a particular substance (see Universals and particulars, below). In a certain sense, Aristotle's method is both inductive and deductive, while Plato's is essentially deductive from a priori principles.[19]
In Aristotle's terminology, "natural philosophy" is a branch of philosophy examining the phenomena of the natural world, and includes fields that would be regarded today as physics, biology and other natural sciences. In modern times, the scope of philosophy has become limited to more generic or abstract inquiries, such as ethics and metaphysics, in which logic plays a major role. Today's philosophy tends to exclude empirical study of the natural world by means of the scientific method. In contrast, Aristotle's philosophical endeavors encompassed virtually all facets of intellectual inquiry.
In the larger sense of the word, Aristotle makes philosophy coextensive with reasoning, which he also would describe as "science". Note, however, that his use of the term science carries a different meaning than that covered by the term "scientific method". For Aristotle, "all science (dianoia) is practical, poetical or theoretical" (Metaphysics 1025b25). By practical science, he means ethics and politics; by poetical science, he means the study of poetry and the other fine arts; by theoretical science, he means physics, mathematics and metaphysics.
If logic (or "analytics") is regarded as a study preliminary to philosophy, the divisions of Aristotelian philosophy would consist of: (1) Logic; (2) Theoretical Philosophy, including Metaphysics, Physics and Mathematics; (3) Practical Philosophy and (4) Poetical Philosophy.
In the period between his two stays in Athens, between his times at the Academy and the Lyceum, Aristotle conducted most of the scientific thinking and research for which he is renowned today. In fact, most of Aristotle's life was devoted to the study of the objects of natural science. Aristotle's metaphysics contains observations on the nature of numbers but he made no original contributions to mathematics. He did, however, perform original research in the natural sciences, e.g., botany, zoology, physics, astronomy, chemistry, meteorology, and several other sciences.
Aristotle's writings on science are largely qualitative, as opposed to quantitative. Beginning in the 16th century, scientists began applying mathematics to the physical sciences, and Aristotle's work in this area was deemed hopelessly inadequate. His failings were largely due to the absence of concepts like mass, velocity, force and temperature. He had a conception of speed and temperature, but no quantitative understanding of them, which was partly due to the absence of basic experimental devices, like clocks and thermometers.
His writings provide an account of many scientific observations, a mixture of precocious accuracy and curious errors. For example, in his History of Animals he claimed that human males have more teeth than females.[20] In a similar vein, John Philoponus, and later Galileo, showed by simple experiments that Aristotle's theory that a heavier object falls faster than a lighter object is incorrect.[21] On the other hand, Aristotle refuted Democritus's claim that the Milky Way was made up of "those stars which are shaded by the earth from the sun's rays," pointing out (correctly, even if such reasoning was bound to be dismissed for a long time) that, given "current astronomical demonstrations" that "the size of the sun is greater than that of the earth and the distance of the stars from the earth many times greater than that of the sun, then ... the sun shines on all the stars and the earth screens none of them."[22]
In places, Aristotle goes too far in deriving 'laws of the universe' from simple observation and over-stretched reason. Today's scientific method assumes that such thinking without sufficient facts is ineffective, and that discerning the validity of one's hypothesis requires far more rigorous experimentation than that which Aristotle used to support his laws.
Aristotle also had some scientific blind spots. He posited a geocentric cosmology that we may discern in selections of the Metaphysics, which was widely accepted up until the 16th century. From the 3rd century to the 16th century, the dominant view held that the Earth was the rotational center of the universe.
Since he was perhaps the philosopher most respected by European thinkers during and after the Renaissance, these thinkers often took Aristotle's erroneous positions as given, which held back science in this epoch.[23] However, Aristotle's scientific shortcomings should not mislead one into forgetting his great advances in the many scientific fields. For instance, he founded logic as a formal science and created foundations to biology that were not superseded for two millennia. Moreover, he introduced the fundamental notion that nature is composed of things that change and that studying such changes can provide useful knowledge of underlying constants.
Geology
As quoted from Charles Lyell's Principles of Geology:
He [Aristotle] refers to many examples of changes now constantly going on, and insists emphatically on the great results which they must produce in the lapse of ages. He instances particular cases of lakes that had dried up, and deserts that had at length become watered by rivers and fertilized. He points to the growth of the Nilotic delta since the time of Homer, to the hallowing of the Palus Maeotis within sixty years from his own time ... He alludes ... to the upheaving of one of the Eolian islands, previous to a volcanic eruption. The changes of the earth, he says, are so slow in comparison to the duration of our lives, that they are overlooked; and the migrations of people after great catastrophes, and their removal to other regions, cause the event to be forgotten.
He says [12th chapter of his Meteorics] 'the distribution of land and sea in particular regions does not endure throughout all time, but it becomes sea in those parts where it was land, and again it becomes land where it was sea, and there is reason for thinking that these changes take place according to a certain system, and within a certain period.' The concluding observation is as follows: 'As time never fails, and the universe is eternal, neither the Tanais, nor the Nile, can have flowed forever. The places where they rise were once dry, and there is a limit to their operations, but there is none to time. So also of all other rivers; they spring up and they perish; and the sea also continually deserts some lands and invades others The same tracts, therefore, of the earth are not some always sea, and others always continents, but everything changes in the course of time.
Physics
Aristotle proposed a fifth element, aether, in addition to the four proposed earlier by Empedocles.
Earth, which is cold and dry; this corresponds to the modern idea of a solid.
Water, which is cold and wet; this corresponds to the modern idea of a liquid.
Air, which is hot and wet; this corresponds to the modern idea of a gas.
Fire, which is hot and dry; this corresponds to the modern ideas of plasma and heat.
Aether which is the divine substance that makes up the heavenly spheres and heavenly bodies (stars and planets).
Each of the four earthly elements has its natural place. All that is earthly tends toward the center of the universe, i.e., the center of the Earth. Water tends toward a sphere surrounding the center. Air tends toward a sphere surrounding the water sphere. Fire tends toward the lunar sphere (in which the Moon orbits). When elements are moved out of their natural place, they naturally move back towards it. This is "natural motion"—motion requiring no extrinsic cause. So, for example, in water, earthy bodies sink while air bubbles rise up; in air, rain falls and flame rises. Outside all the other spheres, the heaven, fifth element, manifested in the stars and planets move in the perfection of circles.
Motion
Aristotle defined motion as the actuality of a potentiality as such Aquinas suggested that the passage be understood literally; that motion can indeed be understood as the active fulfillment of a potential, as a transition toward a potentially possible state. Because actuality and potentiality are normally opposites in Aristotle, other commentators either suggest that the wording which has come down to us is erroneous, or that the addition of the "as such" to the definition is critical to understanding it.
Causality, The Four Causes
Four causes
Aristotle suggested that the reason for anything coming about can be attributed to four different types of simultaneously active causal factors:
Material cause describes the material out of which something is composed. Thus the material cause of a table is wood, and the material cause of a car is rubber and steel. It is not about action. It does not mean one domino knocks over another domino.
The formal cause is its form, i.e., the arrangement of that matter. It tells us what a thing is, that anything is determined by the definition, form, pattern, essence, whole, synthesis or archetype. It embraces the account of causes in terms of fundamental principles or general laws, as the whole (i.e., macrostructure) is the cause of its parts, a relationship known as the whole-part causation. Plainly put the formal cause is the idea existing in the first place as exemplar in the mind of the sculptor, and in the second place as intrinsic, determining cause, embodied in the matter. Formal cause could only refer to the essential quality of causation. A simpler example of the formal cause is the blueprint or plan that one has before making or causing a human made object to exist.
The efficient cause is "the primary source", or that from which the change or the ending of the change first starts. It identifies 'what makes of what is made and what causes change of what is changed' and so suggests all sorts of agents, nonliving or living, acting as the sources of change or movement or rest. Representing the current understanding of causality as the relation of cause and effect, this covers the modern definitions of "cause" as either the agent or agency or particular events or states of affairs, simpler again that which immediately sets the thing in motion. So take the two dominos this time of equal weighting, the first is knocked over causing the second also to fall over. This is effectively efficient cause.
The final cause is its purpose, or that for the sake of which a thing exists or is done, including both purposeful and instrumental actions and activities. The final cause or telos is the purpose or end that something is supposed to serve, or it is that from which and that to which the change is. This also covers modern ideas of mental causation involving such psychological causes as volition, need, motivation or motives, rational, irrational, ethical, and all that gives purpose to behavior.
Additionally, things can be causes of one another, causing each other reciprocally, as hard work causes fitness and vice versa, although not in the same way or function, the one is as the beginning of change, the other as the goal. (Thus Aristotle first suggested a reciprocal or circular causality as a relation of mutual dependence or influence of cause upon effect). Moreover, Aristotle indicated that the same thing can be the cause of contrary effects; its presence and absence may result in different outcomes. Simply it is the goal or purpose that brings about an event (not necessarily a mental goal). Taking our two dominos, it requires someone to intentionally knock the dominos over as they cannot fall themselves.
Aristotle marked two modes of causation: proper (prior) causation and accidental (chance) causation. All causes, proper and incidental, can be spoken as potential or as actual, particular or generic. The same language refers to the effects of causes, so that generic effects assigned to generic causes, particular effects to particular causes, operating causes to actual effects. Essentially, causality does not suggest a temporal relation between the cause and the effect.
Optics
Aristotle held more accurate theories on some optical concepts than other philosophers of his day. The earliest known written evidence of a camera obscura can be found in Aristotle's documentation of such a device in 350 BC in Problemata. Aristotle's apparatus contained a dark chamber that had a single small hole, or aperture, to allow for sunlight to enter. Aristotle used the device to make observations of the sun and noted that no matter what shape the hole was, the sun would still be correctly displayed as a round object. In modern cameras, this is analogous to the diaphragm. Aristotle also made the observation that when the distance between the aperture and the surface with the image increased, the image was magnified.
Chance and spontaneity
According to Aristotle, spontaneity and chance are causes of some things, distinguishable from other types of cause. Chance as an incidental cause lies in the realm of accidental things. It is "from what is spontaneous" (but we can note that what is spontaneous does not come from chance). For a better understanding of Aristotle's conception of "chance" it might be better to think of "coincidence": Something takes place by chance if a person sets out with the intent of having one thing take place, but with the result of another thing (not intended) taking place. For example: A person seeks donations. That person may find another person willing to donate a substantial sum. However, if the person seeking the donations met the person donating, not for the purpose of collecting donations, but for some other purpose, Aristotle would call the collecting of the donation by that particular donator a result of chance. It must be unusual that something happens by chance. In other words, if something happens all or most of the time, we cannot say that it is by chance.
There is also more specific kind of chance, which Aristotle names "luck" that can only apply to human beings, since it is in the sphere of moral actions. According to Aristotle, luck must involve choice (and thus deliberation), and only humans are capable of deliberation and choice. "What is not capable of action cannot do anything by chance".
Metaphysics

Statue of Aristotle (1915) by Cipri Adolf Bermann at the University of Freiburg im Breisgau
Main article: Metaphysics (Aristotle)
Aristotle defines metaphysics as "the knowledge of immaterial being," or of "being in the highest degree of abstraction." He refers to metaphysics as "first philosophy", as well as "the theologic science."
Substance, potentiality and actuality
See also: Potentiality and actuality (Aristotle)
Aristotle examines the concepts of substance and essence (ousia) in his Metaphysics(Book VII), and he concludes that a particular substance is a combination of both matter and form. In book VIII, he distinguishes the matter of the substance as the substratum, or the stuff of which it is composed. For example, the matter of a house is the bricks, stones, timbers etc., or whatever constitutes the potential house, while the form of the substance is the actual house, namely 'covering for bodies and chattels' or any other differentia (see alsopredicables) that let us define something as a house. The formula that gives the components is the account of the matter, and the formula that gives the differentia is the account of the form.[29]
With regard to the change (kinesis) and its causes now, as he defines in his Physics andOn Generation and Corruption 319b-320a, he distinguishes the coming to be from: growth and diminution, which is change in quantity; locomotion, which is change in space; and alteration, which is change in quality.
The coming to be is a change where nothing persists of which the resultant is a property. In that particular change he introduces the concept of potentiality (dynamis) and actuality (entelecheia) in association with the matter and the form.
Referring to potentiality, this is what a thing is capable of doing or being acted upon, if the conditions are right and it is not prevented by something else. For example, the seed of a plant in the soil is potentially (dynamei) plant, and if is not prevented by something, it will become a plant. Potentially beings can either 'act' (poiein) or 'be acted upon' (paschein), which can be either innate or learned. For example, the eyes possess the potentiality of sight (innate – being acted upon), while the capability of playing the flute can be possessed by learning (exercise – acting).
Actuality is the fulfillment of the end of the potentiality. Because the end (telos) is the principle of every change, and for the sake of the end exists potentiality, therefore actuality is the end. Referring then to our previous example, we could say that an actuality is when a plant does one of the activities that plants do.
"For that for the sake of which a thing is, is its principle, and the becoming is for the sake of the end; and the actuality is the end, and it is for the sake of this that the potentiality is acquired. For animals do not see in order that they may have sight, but they have sight that they may see."
In summary, the matter used to make a house has potentiality to be a house and both the activity of building and the form of the final house are actualities, which is also a final cause or end. Then Aristotle proceeds and concludes that the actuality is prior to potentiality in formula, in time and in substantiality.
With this definition of the particular substance (i.e., matter and form), Aristotle tries to solve the problem of the unity of the beings, for example, "what is it that makes a man one"? Since, according to Plato there are two Ideas: animal and biped, how then is man a unity? However, according to Aristotle, the potential being (matter) and the actual one (form) are one and the same thing.[31]
Universals and particulars
Aristotle's predecessor, Plato, argued that all things have a universal form, which could be either a property, or a relation to other things. When we look at an apple, for example, we see an apple, and we can also analyze a form of an apple. In this distinction, there is a particular apple and a universal form of an apple. Moreover, we can place an apple next to a book, so that we can speak of both the book and apple as being next to each other.
Plato argued that there are some universal forms that are not a part of particular things. For example, it is possible that there is no particular good in existence, but "good" is still a proper universal form. Bertrand Russell is a contemporary philosopher who agreed with Plato on the existence of "uninstantiated universals".
Aristotle disagreed with Plato on this point, arguing that all universals are instantiated. Aristotle argued that there are no universals that are unattached to existing things. According to Aristotle, if a universal exists, either as a particular or a relation, then there must have been, must be currently, or must be in the future, something on which the universal can be predicated. Consequently, according to Aristotle, if it is not the case that some universal can be predicated to an object that exists at some period of time, then it does not exist.
In addition, Aristotle disagreed with Plato about the location of universals. As Plato spoke of the world of the forms, a location where all universal forms subsist, Aristotle maintained that universals exist within each thing on which each universal is predicated. So, according to Aristotle, the form of apple exists within each apple, rather than in the world of the forms.
Biology and medicine
In Aristotelian science, most especially in biology, things he saw himself have stood the test of time better than his retelling of the reports of others, which contain error and superstition. He dissected animals but not humans; his ideas on how the human body works have been almost entirely superseded.
Empirical research program

Leopard shark
Aristotle is the earliest natural historian whose work has survived in some detail. Aristotle certainly did research on the natural history of Lesbos, and the surrounding seas and neighbouring areas. The works that reflect this research, such as History of Animals,Generation of Animals, and Parts of Animals, contain some observations and interpretations, along with sundry myths and mistakes. The most striking passages are about the sea-life visible from observation on Lesbos and available from the catches of fishermen. His observations on catfish, electric fish (Torpedo) and angler-fish are detailed, as is his writing on cephalopods, namely, Octopus, Sepia (cuttlefish) and the paper nautilus (Argonauta argo). His description of the hectocotyl arm was about two thousand years ahead of its time, and widely disbelieved until its rediscovery in the 19th century. He separated the aquatic mammals from fish, and knew that sharks and rays were part of the group he called Selachē (selachians).[32]
Another good example of his methods comes from the Generation of Animals in which Aristotle describes breaking open fertilized chicken eggs at intervals to observe when visible organs were generated.
He gave accurate descriptions of ruminants' four-chambered fore-stomachs, and of the ovoviviparous embryological development of the hound shark Mustelus mustelus.[33]
Classification of living things
Aristotle's classification of living things contains some elements which still existed in the 19th century. What the modern zoologist would call vertebrates and invertebrates, Aristotle called 'animals with blood' and 'animals without blood' (he was not to know that complex invertebrates do make use of hemoglobin, but of a different kind from vertebrates). Animals with blood were divided into live-bearing (humans and mammals), and egg-bearing (birds and fish). Invertebrates ('animals without blood') are insects, crustacea (divided into non-shelled – cephalopods – and shelled) and testacea (molluscs). In some respects, this incomplete classification is better than that of Linnaeus, who crowded the invertebrata together into two groups, Insecta and Vermes (worms).
For Charles Singer, "Nothing is more remarkable than [Aristotle's] efforts to [exhibit] the relationships of living things as a scala naturae"[32] Aristotle's History of Animals classified organisms in relation to a hierarchical "Ladder of Life" (scala naturae), placing them according to complexity of structure and function so that higher organisms showed greater vitality and ability to move.[34]
Aristotle believed that intellectual purposes, i.e., final causes, guided all natural processes. Such a teleological view gave Aristotle cause to justify his observed data as an expression of formal design. Noting that "no animal has, at the same time, both tusks and horns," and "a single-hooved animal with two horns I have never seen," Aristotle suggested that Nature, giving no animal both horns and tusks, was staving off vanity, and giving creatures faculties only to such a degree as they are necessary. Noting that ruminants had multiple stomachs and weak teeth, he supposed the first was to compensate for the latter, with Nature trying to preserve a type of balance.[35]
In a similar fashion, Aristotle believed that creatures were arranged in a graded scale of perfection rising from plants on up to man, the scala naturae or Great Chain of Being.[36] His system had eleven grades, arranged according "to the degree to which they are infected with potentiality", expressed in their form at birth. The highest animals laid warm and wet creatures alive, the lowest bore theirs cold, dry, and in thick eggs.
Aristotle also held that the level of a creature's perfection was reflected in its form, but not preordained by that form. Ideas like this, and his ideas about souls, are not regarded as science at all in modern times.
He placed emphasis on the type(s) of soul an organism possessed, asserting that plants possess a vegetative soul, responsible for reproduction and growth, animals a vegetative and a sensitive soul, responsible for mobility and sensation, and humans a vegetative, a sensitive, and a rational soul, capable of thought and reflection.
Aristotle, in contrast to earlier philosophers, but in accordance with the Egyptians, placed the rational soul in the heart, rather than the brain. Notable is Aristotle's division of sensation and thought, which generally went against previous philosophers, with the exception of Alcmaeon.
Psychology
Aristotle's psychology, given in his treatise On the Soul (peri psyche, often known by its Latin title De Anima), posits three kinds of soul("psyches"): the vegetative soul, the sensitive soul, and the rational soul. Humans have a rational soul. This kind of soul is capable of the same powers as the other kinds: Like the vegetative soul it can grow and nourish itself; like the sensitive soul it can experience sensations and move locally. The unique part of the human, rational soul is its ability to receive forms of other things and compare them.
For Aristotle, the soul (psyche) was a simpler concept than it is for us today. By soul he simply meant the form of a living being. Since all beings are composites of form and matter, the form of living beings is that which endows them with what is specific to living beings, e.g. the ability to initiate movement (or in the case of plants, growth and chemical transformations, which Aristotle considers types of movement).
Practical philosophy
Ethics
Aristotle considered ethics to be a practical rather than theoretical study, i.e., one aimed at becoming good and doing good rather than knowing for its own sake. He wrote several treatises on ethics, including most notably, the Nicomachean Ethics.
Aristotle taught that virtue has to do with the proper function (ergon) of a thing. An eye is only a good eye in so much as it can see, because the proper function of an eye is sight. Aristotle reasoned that humans must have a function specific to humans, and that this function must be an activity of the psuchē (normally translated as soul) in accordance with reason (logos). Aristotle identified such an optimum activity of the soul as the aim of all human deliberate action, eudaimonia, generally translated as "happiness" or sometimes "well being". To have the potential of ever being happy in this way necessarily requires a good character (ēthikē aretē), often translated as moral (or ethical) virtue (or excellence).[46]
Aristotle taught that to achieve a virtuous and potentially happy character requires a first stage of having the fortune to be habituated not deliberately, but by teachers, and experience, leading to a later stage in which one consciously chooses to do the best things. When the best people come to live life this way their practical wisdom (phronesis) and their intellect (nous) can develop with each other towards the highest possible human virtue, the wisdom of an accomplished theoretical or speculative thinker, or in other words, aphilosopher.[47]
Politics

Like Aristotle, conservatives generally accept the world as it is; they distrust the politics of abstract reason – that is, reason divorced from experience.
Benjamin Wiker
In addition to his works on ethics, which address the individual, Aristotle addressed the city in his work titled Politics. Aristotle considered the city to be a natural community. Moreover, he considered the city to be prior in importance to the family which in turn is prior to the individual, "for the whole must of necessity be prior to the part".He also famously stated that "man is by nature a political animal." Aristotle conceived of politics as being like an organism rather than like a machine, and as a collection of parts none of which can exist without the others. Aristotle's conception of the city is organic, and he is considered one of the first to conceive of the city in this manner.
The common modern understanding of a political community as a modern state is quite different to Aristotle's understanding. Although he was aware of the existence and potential of larger empires, the natural community according to Aristotle was the city (polis) which functions as a political "community" or "partnership" (koinōnia). The aim of the city is not just to avoid injustice or for economic stability, but rather to allow at least some citizens the possibility to live a good life, and to perform beautiful acts: "The political partnership must be regarded, therefore, as being for the sake of noble actions, not for the sake of living together." This is distinguished from modern approaches, beginning with social contract theory, according to which individuals leave the state of nature because of "fear of violent death" or its "inconveniences." | |
PLATO (c. 428 - 348 B.C.) was a hugely important Greek philosopher and mathematician from the Socratic (or Classical) period.
He is perhaps the best known, most widely studied and most influential philosopher of all time. Together with his mentor,Socrates, and his student, Aristotle, he provided the main opposition to the Materialist view of the world represented by Democritus and Epicurus, and he helped to lay the foundations of the whole of Western Philosophy.
In his works, especially his many dialogues, he blended Ethics, Political Philosophy, Epistemology, Metaphysics and moral psychology into an interconnected and systematic philosophy. In addition to the ideas they contained (such as his doctrine of Platonic, Essentialism, Idealism, his famous theory of Forms and the ideal of "Platonic love.
The philosophical school which he developed at the Academy was known as Platonism (and its later off-shoot, Neo-Platonism). Life | |
Plato was born in Athens (or possibly in Aegina, according to some sources) some time between 429 and 423 B.C. (most modern scholars use estimate of 428 or 427 B.C.) He was possibly originally named Aristocles after his grandfather, and only later dubbed "Plato" or "Platon" (meaning "broad") on account of the breadth of his eloquence, or of his wide forehead, or possibly on account of his generally robust figure.
His father was Ariston (who may have traced his descent from Codrus, the last of the legendary kings of Athens); his mother was Perictione (who was descended from the famous Athenian lawmaker and poet Solon, and whose family also boasted prominent figures of the oligarchic regime of Athens known as the Thirty Tyrants). He had two brothers, Adeimantus and Glaucon, and a sister, Potone. Plato later introduced several of his distinguished relatives into his dialogues, indicating considerable family pride.
When Ariston died early in Plato's childhood, his mother married her own uncle, Pyrilampes, who was also a friend of Pericles (the leader of the democratic faction in Athens), and who had served many times as an ambassador to the Persian court. Together, they had another son, Antiphon, who was therefore Plato's half-brother.
Coming as he did from one of the wealthiest and most politically active families in Athens, Plato must have been instructed in grammar, music and gymnastics by the most distinguished teachers of his time, and certainly his quickness of mind and modesty were widely praised. He had also attended courses of philosophy and was acquainted with Cratylus, a disciple of Heraclitus, before meeting Socrates. This life-changing event occurred when Plato was about twenty years old, and the intercourse between master and pupil probably lasted eight or ten years. As a youth he had loved to write poetry and tragedies, but burnt them all after he became a student of Socrates and turned to philosophy in earnest. It is plain that no influence on Plato was greater than that of Socrates.
During his time in Italy, he also studied with students of Pythagoras and came to appreciate the value of mathematics.
When he returned to Athens in about 385 or 387 B.C., Plato founded the Academy (or Akademia), one of the earliest and most famous organized schools in western civilization and the protoype for later universities, on a plot of land containing asacred grove just outside the city walls of ancient Athens, which had once belonged to the Athenian hero Akademos. Plato had been bitterly disappointed with the standards displayed by those in public office, and his intention was to train young men in philosophy and the sciences in order to create better statesmen, as well as to continue the work of his former teacher, Socrates. Among Plato's more noteworthy students at the Academy were Aristotle, Xenocrates (396 - 314 B.C.), Speusippus(407 - 339 B.C.) and Theophrastus (c. 371 - 287 B.C.).
Except for two more rather ill-advised and ill-fated trips to Syracuse in Sicily in 367 B.C. and 361 B.C. to tutor the young ruler Dionysius II, Plato presided over his Academy from 387 B.C. until his death in 347 B.C., aged about 80. He was supposedly buried in the school grounds, although his grave has never been discovered.
On Plato's death, his nephew Speusippus succeeded him as head of the school (perhaps because his star pupil Aristotle's ideas had by that time diverged too far from Plato's). The school continued to operate for almost 900 years, until A.D. 529, when it was closed by the Byzantine Emperor Justinian I, who saw it as a threat to the propagation of Christianity. Work | |
Plato is perhaps the first philosopher whose complete works are still available to us. He wrote no systematic treatises giving his views, but rather he wrote a number (about 35, although the authenticity of at least some of these remains in doubt) of superb dialogues, written in the form of conversations, a form which permitted him to develop the Socratic method of question and answer. In his dialogues, Plato discussed every kind of philosophical idea, including Ethics (with discussion of the nature of virtue), Metaphysics (where topics include immortality, man, mind, and Realism), Political Philosophy (where topics such as censorship and the ideal state are discussed), Philosophy of Religion (considering topics such as Atheism, Dualism and Pantheism), Epistemology (where he looked at ideas such as a priori knowledge and Rationalism), the Philosophy of Mathematics and the theory of art (especially dance, music, poetry, architecture and drama).
We have no material evidence about exactly when Plato wrote each of his dialogues, nor the extent to which some might have been later revised or rewritten, nor even whether all or part of them were ever "published" or made widely available. In addition to the ideas they contained, though, his writings are also considered superb pieces of literature in their own right, in terms of the mastery of language, the power of indicating character, the sense of situation, and the keen eye for both tragic and comic aspects.
None of the dialogues contain Plato himself as a character, and so he does not actually declare that anything asserted in them are specifically his own views. The characters in the dialogues are generally historical, with Socrates usually as the protagonist (particularly in the early dialogues). It is generally thought that the views expressed by the character of Socrates in Plato's dialogues were views that Socrates himself actually held, and the works had the effect of gradually rehabilitating Socrates's rather tarnished image among Athenians in the wake of his death. As time went on, though, the dialogues began to deal more with subjects that interested Plato himself, rather than merely providing a vehicle for the ideas of Socrates. It seems likely that Plato's main intention in his dialogues was more to teach his students to think for themselves and to find their own answers to the big questions, rather than to blindly follow his own opinions (or those of Socrates).
Among the (likely earlier) Socratic dialogues are: "Apology", "Charmides", "Crito", "Euthyphro", "Ion", "Laches", "Lesser Hippias", "Lysis", "Menexenus" and "Protagoras". The following are often considered "transitional" dialogues: "Gorgias","Meno" and "Euthydemus". The middle dialogues are generally seen as the first appearances of Plato's own views:"Cratylus", "Phaedo", "Phaedrus", "Symposium", "Republic", "Theaetetus" and "Parmenides". The late dialogues probably indicate Plato's more mature thought, including criticisms of his own theories: "Sophist", "Statesman", "Philebus","Timaeus", "Critias" and "Laws". The huge "Republic" in particular is considered one of the single most influential works in the whole of Western Philosophy, although his account of Socrates' trial in the "Apology" may be the most read.
Central to Plato's Metaphysics is his theory of Platonic Realism, which inverts the common sense intuition about what is knowable and what is real. Confusingly, this is also known as Platonic Idealism, and indeed Idealism may be a better description. Plato believed that universals (those properties of an object which can exist in more than one place at the same time e.g. the quality of "redness") do in fact exist and are real. However, they exist in a different way than ordinary physical objects exist, in a sort of ghostly mode of existence, unseen and unfelt, outside of space and time, but not at any spatial or temporal distance from people's bodies (a type of Dualism).
Part and parcel of Plato's Platonic Realism is his theory of Forms or Ideas, which refers to his belief that the material world as it seems to us is not the real world, but only a shadow or a poor copy of the real world. This is based on Plato's concept (or Socrates' through Plato) of hylomorphism, the idea that substances are forms inhering in matter. He held that substance is composed of matter and form, although not as any kind of a mixture or amalgam, but composed homogeneously together such that no matter can exist without form (or form without matter). Thus, pure matter and pure form can never be perceived, only comprehended abstractly by the intellect.
Forms, roughly speaking, are the pure and unchanging archetypes or abstract representations of universals and of all the things we see around us, and they are in fact the true basis of reality. These ideal Forms are instantiated by one or many different particulars, which are essentially material copies of the Forms, and make up the world we perceive around us. Plato was therefore one of the first Essentialists in that he believed that all things have essences or attributes that make an object or substance what it fundamentally is. According to Plato, true knowledge or intelligence is the ability to grasp the world of Forms with one's mind, even though his evidence for the existence of Forms is intuitive only.
This idea was most famously captured and illustrated in Plato's Allegory of the Cave, from his best-known work, "The Republic". He represented man's condition as being chained in the darkness of a cave, with only the false light of a fire behind him. He can perceive the outside world solely by watching the shadows on the wall in front of him, not realizing that this view of existence is limited, wrong or in any way lacking (after all, it is all he knows). Plato imagined what would occur if some of the chained men were suddenly released from this bondage and let out into the world, to encounter the divine light of the sun and perceive “true” reality. He described how some people would immediately be frightened and want to return to the familiar dark existence of the cave, while the more enlightened would look at the sun and finally see the world as it truly is. If they were then to return to the cave and try to explain what they had seen, they would be mocked mercilessly and called fanciful, even mad. In the allegory, Plato saw the outside world, which the cave's inhabitants glimpsed only in a second-hand way, as the timeless realm of Forms, where genuine reality resides. The shadows on the wall represent the world we see around us, which we assume to be real, but which in fact is a mere imitation of the real thing.
Plato's theory of Forms was essentially an attempt to solve the dichotomy between Parmenides' view (that there is no real change or multiplicity in the world, and that reality is one) and that of Heraclitus (that motion and multiplicity are real, and that permanence is only apparent) by means of a metaphysical compromise. Plato himself, though, was well aware of the limitations of his theory, and in particular he later concocted the "Third Man Argument" against his own theory: if a Form and a particular are alike, then there must be another (third) thing by possession of which they are alike, leading to an infinite regression. In a later (rather unsatisfactory) version of the theory, he tried to circumvent this objection by positing that particulars do not actually exist as such: rather, they "mime" the Forms, merely appearing to be particulars.
In the "Timaeus", Plato gave his account of the natural sciences (physics, astronomy, chemistry and biology) and the creation of the universe by the Demiurge. Unlike the creation by the God of medieval theologians, Plato's Demiurge did not create out of nothing, but rather ordered the cosmos out of already-existing chaotic elemental matter, imitating the eternal Forms. Plato took the four elements (fire, air, water and earth), which he proclaimed to be composed of various aggregates of triangles, and made various compounds of these into what he called the Body of the Universe.
In recent years, more emphasis has been placed on Plato's unwritten teachings, which were passed on orally to his students and not included in the dialogues (on several occasions, Plato stressed that the written transmission of knowledge was fault yond inferior to the spoken logos). We have at least some idea of this from reports by his students, Aristotle and others, and from the continuity between his teachings and the interpretations of Plotinus and the Neo-Platonists. One recurring theme is that the first principle of everything, including the causation of good and of evil and of the Forms themselves, is the One (the cause of the essence of the Forms). It can be argued, then, that Plato's concept of God affirms Monotheism, although he also talked of an Indefinite Duality (which he also called Large and Small).
In Epistemology, although some have imputed to Plato the remarkably modern analytic view that knowledge is justified true belief, Plato more often associated knowledge with the apprehension of unchanging Forms and their relationships to one another. He argued that knowledge is always proportionate to the realm from which it is gained, so that, if one derives an account of something experientially then (because the world of sense is always in flux) the views attained will be mere opinions. On the other hand, if one derives an account of something by way of the non-sensible Forms, then the views attained will be pure and unchanging (because the Forms are unchanging too). In several dialogues, Plato also floated the idea that knowledge is a matter of recollection ("anamnesis"), and not of learning, observation or study. Thus, knowledge is not empirical, a but essentially comes from divine insight.
To a large extent, it is Plato who is responsible for the modern view of the Sophist as a greedy and power-seeking instructor who uses rhetorical sleight-of-hand and ambiguities of language in order to deceive, or to support fallacious reasoning. He was at great pains in his dialogues to exonerate Socrates from accusations of Sophism. Plato, and Aristotle after him, also believed in a kind of Moral Universalism (or Moral Absolutism), opposing the Moral Relativism of the Sophists.
In Ethics, Plato had a teleological or goal-orientated worldview, and the aim of his Ethics was therefore to outline the conditions under which a society might function harmoniously. He considered virtue to be an excellence of the soul, and, insofar as the soul has several components (e.g. reason, passions, spirit), there will be several components of its excellence: the excellence of reason is wisdom; the excellence of the passions are attributes such as courage; and the excellence of the spirit Is temperance. Finally, justice is that excellence which consists in a harmonious relation of the other three parts. He believed, then, that virtue was a sort of knowledge (the knowledge of good and evil) that is required to reach the ultimate good (oreudaimonia), which is what all human desires and actions aim to achieve, and as such he was an early proponent of Eudaimonism or Virtue Ethics.
Plato's philosophical views had many societal and political implications, especially on the idea of an ideal state or government (much influenced by the model of the severe society of Sparta), although there is some discrepancy between his early and later views on Political Philosophy. Some of his most famous doctrines are contained in the "Republic" (the earliest example of a Utopia, dating from his middle period), as well as in the later "Statesman" and the "Laws".
In general terms, Plato drew parallels between the tripartite structure of the individual soul and body ("appetite-stomach", "spirit-chest" and "reason-head") and the tripartite class structure of societies. He divided human beings up, based on their innate intelligence, strength and courage, into: the Productive (Workers), laborers, farmers, merchants, etc, which corresponds to the "appetite-stomach"; the Protective (Warriors), the adventurous, strong and brave of the armed forces, which corresponds to the "spirit-chest"; and the Governing (Rulers or Philosopher Kings), the intelligent, rational, self-controlled and wise, who are well suited to make decisions for the community, which corresponds to the "reason-head". The Philosophers and the Warriors together are thus the Guardians of Plato's ideal state.
Plato concluded that reason and wisdom (rather than rhetoric and persuasion) should govern, thus effectively rejecting the principles of Athenian democracy (as it existed in his day) as only a few are fit to rule. A large part of the "Republic" then addresses how the educational system should be set up (his important contribution to the Philosophy of Education) to produce these Philosopher Kings, who should have their reason, will and desires united in virtuous harmony (a moderate love for wisdom, and the courage to act according to that wisdom). The Philosopher King image has been used by many after Plato to justify their personal political beliefs.
He also made some interesting arguments about states and rulers. He argued that it is better to be ruled by a tyrant (since then there is only one person committing bad deeds) than by a bad democracy (since all the people are now responsible for the bad actions). He predicted that a state which is made up of different kinds of souls will tend to decline from an aristocracy (rule by the best) to a timocracy (rule by the honorable), then to an oligarchy (rule by the few), then to a democracy (rule by the people) and finally to tyranny (rule by a single tyrant).
In the "Laws", probably Plato's last work and a work of enormous length and complexity, he concerned himself with designing a genuinely practicable (if admittedly not ideal) form of government, rather than with what a best possible state might be like. He discussed the empirical details of statecraft, fashioning rules to meet the multitude of contingencies that are apt to arise in the "real world" of human affairs, and it marks a rather grim and terrifying culmination of the totalitarian tendencies in his earlier political thought.
Plato's views on Aesthetics were somewhat compromised and he had something of a love-hate relationship with the arts. He believed that aesthetically appealing objects were beautiful in and of themselves, and that they should incorporate proportion, harmony and unity among their parts. As a youth he had been a poet, and he remained a fine literary stylist and a great story-teller. However, he found the arts threatening in that they are powerful shapers of character. Therefore, to train and protect ideal citizens for an ideal society, he believed that the arts must be strictly controlled, and he proposed excluding poets, playwrights and musicians from his ideal Republic, or at least severely censoring what they produced. He also argued that art is merely imitation of the objects and events of ordinary life, effectively a copy of a copy of an ideal Form. Art is therefore even more of an illusion than is ordinary experience, and so should be considered at best entertainment, and at worst a dangerous delusion.
In the "Symposium" and the "Phaedrus", Plato introduces his theory of erôs or love, which has come to be known as “Platonic love". Although he invented the image of two lovers being each other's "other half", he clearly regards actual physical or sexual contact between lovers as degraded and wasteful forms of erotic expression. Thus, unless the power of love is channelled into "higher pursuits" (culminating in the knowledge of the Form of Beauty), it is doomed to frustration, and people sadly squander the real power of love by limiting themselves to the mere pleasures of physical beauty. On an unrelated note, he is also responsible for the famous myth of Atlantis, which first appears in the "Timaeus".
Plato's consideration of epistemology, or the theory of knowledge, comes mainly in the "Theaetetus". In it, he (through the person of Socrates) considers three different theses - that knowledge is perception, that knowledge is true judgment, and that knowledge is true judgment together with an account - refuting each of them in turn, without leaving us with any definitive conclusion or solution. One is left, though; with the impression that Plato's own view is probably that what constitutes knowledge is actually a combination or synthesis of all these separate theses.
Although the study of Plato's thought continued with the Neo-Platonists, his reputation was completely eclipsed during Medievaltimes by that of his most famous student, Aristotle. This is mainly because Plato's original writings were essentially lost to Western civilization until they were brought from Constantinople in the century before its fall by the Greek Neo-Platonists George Gemistos Plethon (c. 1355 - 1452). The Medieval Scholastic philosophers, therefore, did not have access to the works of Plato, nor the knowledge of Greek needed to read them. Only during the Renaissance, with the general resurgence of interest in classical civilization, did knowledge of Plato's philosophy become widespread again in the West, and many of the greatest early modern scientists and artists who broke with Scholasticism saw Plato's philosophy as the basis for progress in the arts and sciences. By the 19th Century, Plato's reputation was restored, and at least on par with Aristotle's.
Plato's influence has been especially strong in mathematics and the sciences. Although he made no important mathematical discoveries himself, his belief that mathematics provides the finest training for the mind was extremely important in the development of the subject (over the door of the Academy was written, "Let no one unversed in geometry enter here"). He concentrated on the idea of "proof", insisting on accurate definitions and clear hypotheses, all of which laid the foundations for the systematic approach to mathematics of Euclid (who flourished around 300 B.C.)
However, Plato also helped to distinguish between pure and applied mathematics by widening the gap between "arithmetic"(now called Number Theory) and "logistic" (now called Arithmetic). Plato's resurgence in the Modern era further inspired some of the greatest advances in Logic since Aristotle, primarily through Gottlob Frege and his followers Kurt Gödel (1906 - 1978),Alonzo Church (1903 - 1995) and Alfred Tarski (1901 - 1983).
Plato's name is also attached to the "Platonic solids" (convex regular polyhedrons), especially in the "Timaeus", in which the cube, tetrahedron, octahedron, and icosahedron are given as the shapes of the atoms of earth, fire, air and water, with the fifth Platonic solid, the dodecahedron, being his model for the whole universe. Plato's beliefs as regards the universe were that the stars, planets, Sun and Moon all move round the Earth in crystalline spheres. The sphere of the Moon was closest to the Earth, then the sphere of the Sun, then Mercury, Venus, Mars, Jupiter, Saturn and furthest away was the sphere of the stars. He believed that the Moon shines by reflected sunlight.