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social contract theory

Belief that political structures and the legitimacy of the state derive from an (explicit or implicit) agreement by individual human beings to surrender (some or all of) their private rights in order to secure the protection and stability of an effective social organization or government. Distinct versions of social contract theory were proposed by Hobbes, Locke, Rousseau, and Rawls.

Recommended Reading: Social Contract: Essays by Locke, Hume, and Rousseau, ed. by Ernest Barker (Oxford, 1962); The Social Contract Theorists: Critical Essays on Hobbes, Locke, and Rousseau, ed. by Christopher W. Morris (Rowman & Littlefield, 1999); Brian Skyrms, Evolution of the Social Contract (Cambridge, 1996); John Rawls, The Law of Peoples (Harvard, 2001); and Patrick Riley, Will and Political Legitimacy: A Critical Exposition of Social Contract Theory in Hobbes, Locke, Rousseau, Kant, and Hegel (iUniverse, 1999).

Also see SEP on contractarianism and contemporary approaches, IEP, EB, and Stephen Daniel.

Socrates (470-399 B.C.E.)

Greek philosopher. He was the teacher of Plato, from whom we have our best knowledge of his philosophical methods. Although he wrote nothing, Socrates left Western philosophy the rich legacy of his example in the persistent pursuit of truth.

For a discussion of his life and work, see Socrates.


Belief that only I myself and my own experiences are real, while anything else—a physical object or another person—is nothing more than an object of my consciousness. As a philosophical position, solipsism is usually the unintended consequence of an over-emphasis on the reliability of internal mental states, which provide no evidence for the existence of external referents.

Recommended Reading: Gilbert Ryle, The Concept of Mind (Chicago, 1984); P. F. Strawson, Individuals: an Essay in Descriptive Metaphysics (Routledge, 1979); and Albert A. Johnstone, Rationalized Epistemology: Taking Solipsism Seriously (SUNY, 1991).

Also see IEP, EB, and ISM.

σοφια [sophía]

Greek term for the intellectual virtue of wisdom, in contrast with the more practical function of φρνησις [phrónêsis]. According to Plato, this is the distinctive feature of rulers in the ideal state and the crowning achievement of the rational soul of an individual.

Recommended Reading: F. E. Peters, Greek Philosophical Terms: A Historical Lexicon (NYU, 1967).

Also see PP.


A plausible argument that is actually fallacious, especially when someone dishonestly presents it as if it were legitimate reasoning.

Also see SEP.


Presocratic philosophers who offered to teach young Athenians how to use logic and rhetoric to defeat opponents in any controversy. Socrates and Plato sharply criticized most of the sophists because they accepted monetary rewards for encouraging unprincipled persuasive methods.

Recommended Reading: W. K. C. Guthrie, The Sophists (Cambridge, 1971); The Older Sophists, ed. by Rosamond Kent Sprague (Hackett, 2001); The First Philosophers: The Presocratics and Sophists, ed. by Robin Waterfield (Oxford, 2000); and Susan C. Jarratt, Rereading the Sophists: Classical Rhetoric Refigured (Southern Illinois, 1998).

Also see SEP, IEP, EB, PP, and CE.

σωφροσυνη [sôphrosúnê]

Greek term for moderation, the capacity to exercise self-control over one's desire for pleasure. For Plato, this is the virtue best exemplified by the masses in the ideal state. According to Aristotle, however, σωφρουνη is even more crucial, since every moral virtue is properly conceived as the mean between vicious extremes.

Recommended Reading: F. E. Peters, Greek Philosophical Terms: A Historical Lexicon (NYU, 1967).

Also see PP.


A complex variety of argument consisting entirely of categorical syllogisms linked together by the use of the same propositions as the conclusions of some and the premises of others.

Example: "Some pets are cardinals, but all cardinals are finches, while every finch is a bird, and only warm-blooded animals are birds. Hence, some pets are birds."

Applied to vague predicates, such chains of reasoning may result in paradox: if one grain of sand does not make a heap, and the addition of a second grain of sand does not make a heap, and the addition of a third grain of sand does not make a heap, etc., etc., then it would seem to follow (contrary to fact) that a collection of ten billion grains of sand must not be a heap.

Recommended Reading: Lewis Carroll, Symbolic Logic & Game of Logic (Dover, 1958) and Linda Claire Burns, Vagueness: An Investigation into Natural Languages and the Sorites Paradox (Kluwer, 1991).

Also see SEP and EB.

soul {Gk. ψυχη [psychê]; Lat. anima}

The active principle present in living things. Plato distinguished three distinct components of the human soul, and Aristotle supposed that plants and animals, no less than human beings, have souls of some sort. Under the influence of Christianity, medieval philosophers focussed on the intellectual component of the human soul, and Descartes identified it as an immaterial substance.

Recommended Reading: Plato, Phaedo (Oxford, 1999); Aristotle, De Anima / On the Soul (Penguin, 1987); Thomas Aquinas, On Human Nature (Hackett, 1999); Jan N. Bremmer, The Early Greek Concept of the Soul (Princeton, 1987); and Whatever Happened to the Soul? Scientific and Theological Portraits of Human Nature, ed. by Warren S. Brown, Nancey C. Murphy, and H. Newton Malony (Fortress, 1998).

Also see SEP, EB, and CE.

sound / unsound

Distinction among deductive arguments. A sound argument both has true premises and employs a valid inference; its conclusion must therefore be true. An unsound argument either has one or more false premises or relies upon an invalid inference; its conclusion may be either true or false.

Souvré, Madeleine de, Marquise de Sablé (1599-1678)

French intellectual leader. Madame de Sablé hosted an influential salon at Port-Royal and wrote Maximes et Pensees Diverses (Moral Maxims and Reflections) (1691) summarizing her view of human nature.

speech acts

The complex group of things we typically perform when speaking. J. L. Austin famously distinguished the simple locutionary act of saying something meaningful, the force of the illocutionary act of employing this language for some purpose, and the further perlocutionary act of having an actual effect on those who hear the utterance.

Thus, for example, in saying (locution) to a friend, "That's an ugly necktie," I may also insult him (illocution) and persuade him to dress differently (perlocution).

Recommended Reading: J. L. Austin, Philosophical Papers, ed. by Geoffrey J. Warnock and J. O. Urmson (Oxford, 1990); J. L. Austin, How to Do Things With Words, ed. by Marina Sbisa and J. O. Urmson (Harvard, 1975); and John R. Searle, Speech Acts (Cambridge, 1970).

Also see SEP and EB.

Spencer, Herbert (1820-1903)

English philosopher whose Education (1861) promoted a scientific approach to the creative development of intellect. In the systematic philosophical work that began with First Principles (1862) Spencer tried to generalize from Darwinian evolution a comprehensive account of progress in human knowledge, morality, and society. The political views expressed in Man versus the State (1884) include a nearly absolute defence of individual liberty and a strict opposition to governmental interference.

Recommended Reading: Herbert Spencer, Principles of Ethics, ed. by Tibor R. Machan (Liberty Fund, 1981); W. H. Hudson, An Introduction to the Philosophy of Herbert Spencer (Thoemmes, 1999); Robert G. Perrin, Herbert Spencer: A Primary and Secondary Bibliography (Garland, 1993); and Herbert Spencer and the Limits of the State: The Late Nineteenth-Century Debate Between Individualism and Collectivism, ed. by Michael Taylor (St. Augustine, 1996).

Also see SEP, IEP, EB, Andy Blunden, and ELC.

Spinoza, Baruch (1632-1677)

Portuguese-Dutch Jewish philosopher who developed a monistic account of the universe as a single infinite substance (god or nature) whose essential features flow with logical necessity and include as modes every finite being.

For a discussion of his life and works, see Spinoza.

square of opposition

In traditional categorical logic, a diagram representing the logical relationships that hold among propositions of different forms with the same terms:

    "All S are P."  (A)- - - - - - -(E)  "No S are P."
                     | *           * |
                         *       *
                     |     *   *     |
                     |     *   *     |
                         *       *
                     | *           * |
   "Some S are P."  (I)---  ---  ---(O)  "Some S are not P."

In this square, the contradictories are across from each other diagonally, the contraries are across the top and the subcontraries across the bottom, and subalternation holds on each side.

Also see SEP and EB.

Staël-Holstein, Anne Louise Germaine Necker, Baronne de (1766-1817)
de Staël

French novelist, essayist, and philosopher. Although her controversial political views were often condemned, Madame de Staël's De l'influence des passions sur le boneur des individuals et des nations (A Treatise on the Influence of the Passions on the Happiness of Individuals and of Nations) (1796) was the chief source of her generation's information about the philosophies of Rousseau and Kant, while her De l'Allemagne (On Germany) emphasized the work of Fichte, Schelling, and the Romantics.

Recommended Reading: Germaine De Stael, Politics, Literature, and National Character, tr. by Monroe Berger (Transaction, 2000); Major Writings of Germaine De Stael, ed. by Vivian Folkenflik (Columbia, 1992); and J. Christopher Herold, Mistress to an Age (Greenwood, 1975).

Also see EB.

standard form

A consistent way of organizing deductive arguments. The standard form for a categorical syllogism is:

Major Premise,
Minor Premise,

Stanton, Elizabeth Cady (1815-1902)

American journalist and political activist, author of Degradation of Disenfranchisement (1892) and The Woman's Bible (1898), where she postulated an androgynous deity and defended the historical reality of matriarchy. Stanton founded the National Woman's Suffrage Association and devoted her career to the abolition of slavery and efforts to secure the rights of women to vote. Her speech "Dare to Question" argues for a strict separation between church and state.

Recommended Reading: The Elizabeth Cady Stanton-Susan B. Anthony Reader: Correspondence, Writings, Speeches, ed. by Ellen Carol Dubois and Gerda Lerner (Northeastern, 1992); Elizabeth Cady Stanton: A Radical for Woman's Rights, ed. by Lois W. Banner and Oscar Handlin (Little, Brown, 1995); Elisabeth Griffith, In Her Own Right: The Life of Elizabeth Cady Stanton (Oxford, 1985); and Geoffrey C. Ward, Martha Saxton, Ann D. Gordon, Ellen Carol Dubois, and Paul Barnes, Not for Ourselves Alone: The Story of Elizabeth Cady Stanton & Susan B. Anthony: An Illustrated History (Knopf, 1999).

Also see EB.


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