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Tillich, Paul (1886-1965)

German-American theologian. Tillich's Systematic Theology (1951-1964) [vol. 1 and vol. 2 ] defines religion as the most ultimate of all human concerns, identifies god with the ground of all being, and treats religious language and ritual as symbolic. In The Courage to Be (1952) Tillich employed central concepts from existentialism to recommend a life of personal authenticity in the face of cultural and political obstacles.

Recommended Reading: Paul Tillich, Theology of Culture, ed. by Robert C. Kimball (Oxford, 1959); Paul Tillich, Dynamics of Faith (Harpercollins, 1986); The Essential Tillich: An Anthology of the Writings of Paul Tillich, ed. by F. Forrester Church (Chicago, 1999); John Heywood Thomas, Tillich (Continuum, 2000); and Richard Grigg, Symbol and Empowerment: Paul Tillich's Post-Theistic System (Mercer, 1985).

Also see Stephen Palmquist, EB, and ELC.

time {Ger. Zeit}

Temporal duration. Philosophers have traditionally addressed such questions as: whether time is an independent feature of reality or merely an aspect of our experience; whether or not it makes sense to think of time as having had a beginning; why time is directional and the past and future are asymmetrical; whether time flows continuously or is composed of discrete moments; whether there is absolute time in addition to relations of temporal succession; and whether it is possible to travel through time.

The Eleatics developed general arguments to show that time and motion are impossible, and Augustine employed the analysis of time to explain human freedom in the face of divine power. Leibniz maintained that time is nothing more than temporal relations, Newton and Clarke defended its absolute character, and Kant tried to mediate by regarding space and time as pure forms of sensible intuition. Later idealists commonly followed McTaggart in denying the reality of time.

Recommended Reading: The New Theory of Time, ed. by L. Nathan Oaklander and Quentin Smith (Yale, 1994); Martin Heidegger, History of the Concept of Time, tr. by Theodore Kisiel (Indiana, 1992); Michael Tooley, Time, Tense, and Causation (Oxford, 2000); David Z. Albert, Time and Chance (Harvard, 2000); Theodore Sider, Four-Dimensionalism: an Ontology of Persistence and Time (Oxford, 2001); L. Nathan Oaklander, Temporal Relations and Temporal Becoming (Univ. Pr. of Am., 1984); and Michael Friedman, Foundations of Space-Time Theories (Princeton, 1986).

Also see SEP on time, the experience of time, temporal logic, temporal parts, and the conventionality of simultaneity, IEP, EB, J. R. Lucas, David L. Thompson, Dennett & Kinsbourne, and CE.

τιμη [timê]

Greek term for honor, esteem, or dignity. Thus, for Plato, a timocratic society or person is unduly governed by concern for public dignity or reputation.

Also see PP.

time travel

The philosophy of time travel assumes that travel to the past is physically possible and proceeds to discuss the philosophical consequences of this assumption:

  • Changing The Past: If it is possible to return to the past then it follows that it I possible to change the past. It the past is changed then something both did and did not happen and this is a contradiction.
  • There is Nowhere to Go: Time travel to the past assumes that times are in some sense still there. If not, there is simply no destination for the time traveller.
  • Causal Anomalies: Time travel opens up the apparent possibility for anomalous causal chains. Typical examples in the literature are being your own parent or sending back photographs of Van Gogh's paintings to Van Gogh as a ten year old. These causal anomalies, though strange, do not appear to be contradictory.
  • Self Defeating Causal Chains: If time travel is possible then this entails the possibility of a causal chain cancelling itself out, as when returning to your past and killing your infant self.
To the above objections to time travel there are many counter-arguments in the literature. [Contributed by Mat Ripley.]

Recommended Reading: W. Godfrey-Smith, "Travelling in Time" (Analysis 40, 1980); J. Harrison, "Problem No. 18" (Analysis 39, 1979); J. Harrison, "Dr Who and the Philosophers" (Aristotelian Sup. Vol. 45, 1971); Paul Horwich, Asymmetries in Time: Problems in the Philosophy of Science (MIT, 1987); Paul Horwich, "On Some Alleged Paradoxes of Time Travel" (Journal of Philosophy 72, 1975); David Lewis, "The Paradoxes of Time Travel" (American Philosophical Quarterly 13, 1976); M. Macbeath, "Who was Dr Who's Father?" (Synthesis 51, 1982); Paul J. Nahin, Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction (Springer Verlag, 1991); Hilary Putnam, "It Ain't Necessarily So" (Journal of Philosophy 63, 1962); J.J.C. Smart, "Is Time Travel Possible?" (Journal of Philosophy 60, 1963); and D. Williams, "The Myth of Passage" (Journal of Philosophy 48, 1951).

Also see SEP on time travel and time machines.

Timon of Philius (320-230 BCE)

Greek skeptic who expounded and defended the views of Pyrrhonism by offering satirical commentary on the works of Plato, Aristotle, and other Greek philosophers.

Also see SEP, IEP, EB, and ELC.


A particular instance of a word or sign, as opposed to the abstract kind or type it exemplifies. Thus, for example, the preceding sentence is 18 words long (token), but contains only 16 words (type), since "a" and "or" are each used twice.

Toland, John (1670-1722)

English philosopher. Toland's Christianity not Mysterious (1696) offered a purely rational defense of god's existence and relation to the natural world, marking a transition between the philosophy of John Locke and the rise of Deism.

Recommended Reading: Robert Rees Evans, Pantheisticon: The Career of John Toland (Peter Lang, 1991); Stephen Daniel, John Toland: His Methods, Manners, and Mind (McGill Queens, 1984); and Thomas Duddy, A History of Irish Thought (Routledge, 2002).

Also see EB.

transcendental argument

Reasoning from the fact that we do have experiences or engage in practices of a certain sort to the truth of those conditions without which these experiences or practices would not be possible. Kant employed transcendental arguments to establish our synthetic yet a priori knowledge of mathematics and natural science as features of the world as it appears to us. Strawson employs a similar pattern of reasoning to show that our identification of particulars presupposes the existence of material objects.

Recommended Reading: Immanuel Kant, Critique of Pure Reason, tr. by Werner S. Pluhar and Patricia Kitcher (Hackett, 1996); F. C. White, Kant's First Critique and the Transcendental Deduction (Avebury, 1996); Henry E. Allison, Kant's Transcendental Idealism: An Interpretation and Defense (Yale, 1986); and Frederick C. Doepke, The Kinds of Things: A Theory of Personal Identity Based on Transcendental Argument (Open Court, 1996).

Also see SEP and EB.

Transposition (Trans.)

A rule of replacement of the form:

	( p ⊃ q ) ≡ ( ~ q ⊃ ~ p )

Example: "If it produces pleasure, then it is right." is equivalent to "If it isn't right, then it doesn't produce pleasure."

A simple truth-table shows the reliability of inferences of this sort.

triad, Hegelian

See thesis / antithesis / synthesis.

Trotsky, Leon (Lev Davidovich Bronstein) (1879-1940)

Russian social and political philosopher who participated in the Bolshevik revolution but was later exiled by Stalin. Although he often expressed respect for the psychological theories of Freud, Trotsky's effort to establish philosophical foundations for the political theories of Marx in the later book In Defence of Marxism emphasized a narrow reliance on dialectical materialism as a comprehensive view of social reality.

Recommended Reading: Leon Trotsky, The Revolution Betrayed: What Is the Soviet Union and Where Is It Going (Mehring, 1990); Leon Trotsky, History of the Russian Revolution (Pathfinder, 1980); Dmitri Volkogonov, Trotsky: The Eternal Revolutionary, tr. by Harold Shukman (Free Press, 1996); and Alex Callinicos, Trotskyism (Minnesota, 1990).

Also see Fred Buch, EB, and Pegasos.

truth {Gk. αληθεια [alêtheia]; Lat. veritas; Ger. Wahrheit}

The conformity of a proposition to the way things are. Precise analysis of the nature of truth is the subject of the correspondence, coherence, pragmatic, redundancy, and semantic theories of truth.

Recommended Reading: Theories of Truth, ed. by Paul Horwich (Dartmouth, 1994); Colin McGinn, Logical Properties (Oxford, 2001); , ed. by Volker Halbach and Leon Horsten (Hänsel-Hohenhausen, 2002); Max Kölbel, Truth Without Objectivity (Routledge, 2002); Hartry Field, Truth and the Absence of Fact (Oxford, 2001); and Richard L. Kirkham, Theories of Truth: A Critical Introduction (Bradford, 1995).

Also see SEP on truth, truthlikeness, Tarski's truth definitions, and the correspondence, coherence, deflationary, identity, and revision theories of truth, EB, and Norman Swartz.


A compound statement or connective is truth-functional if its truth or meaning is wholly determined by the possible combinations of truth-value of its component statements.

Also see SEP and EB.


A simple chart showing the possible combinations of truth-values for a statement form or an argument form in the propositional calculus.

Also see EB.

Truth, Sojourner (Isabella Baumfree van Wagener) (1797-1883)
Sojourner Truth

American advocate for human rights. After her emancipation from slavery, Sojourner Truth became famous as public speaker; one of her best-known orations is Ain't I a Woman? (1851), an eloquent plea for recognition of the dignity of working-class women. The Narrative of Sojourner Truth, a Bondswoman of Olden Time (dictated to Olive Gilbert in 1850) is a clear statement of her principled defence of women's rights, temperance, and the abolition of slavery.

Recommended Reading: Sojourner Truth, Book of Life (X-Press, 1999) and Nell Irvin Painter, Sojourner Truth: A Life, a Symbol (Norton, 1997).

Also see EB.

τυχη [tychê]

Greek term for fortune, luck, or chance, as opposed to the necessity {Gk. αναγκη [anankê]} of logical or causal connections. In moral life, especially, this significantly diminishes the tendency of virtue to produce happiness with any regularity or certainty.

Recommended Reading: F. E. Peters, Greek Philosophical Terms: A Historical Lexicon (NYU, 1967); Martha C. Nussbaum, The Fragility of Goodness: Luck and Ethics in Greek Tragedy and Philosophy (Cambridge, 2001); Bernard Williams, Moral Luck (Cambridge, 1982); and Claudia Card, The Unnatural Lottery: Character and Moral Luck (Temple, 1996).

Also see IEP, SEP, Paul Schollmeier, and PP.

tu quoque

The informal fallacy of replying to criticism by arguing that one's opponent is guilty of something equally improper.

Example: "Republicans claim that Democrats make illegal use of campaign funds. But they do the same thing themselves, so there is no reason to enforce campaign finance laws."

This fallacy is usefully regarded as a special case of the circumstantial ad hominem argument.

Also see FF.

Turing, Alan Mathison (1912-1954)

English mathematician. Extrapolating from the mathematical discoveries of Gödel, Turing proposed in Computing Machinery and Intelligence (1950) a specific description of just what an idealized machine could, in principle, compute. In addition to its practical importance for the development of digital computing equipment, Turing's theory provides support for a functionalist account of the mind by proposing the practical test of whether or not we would attribute intelligence to a system whose performance is indistinguishible from that of a human agent.

Recommended Reading: Alan Mathison Turing, Mathematical Logic (Elsevier, 2001); Andrew Hodges, Alan Turing: The Enigma (Walker, 2000); Andrew Hodges, Turing (Routledge, 1999); and Machines and Thought: The Legacy of Alan Turing, ed. by Peter Millican and Andy Clark (Oxford, 1999).

On the Turing machine, also see SEP on Turing, the Turing machine, the Turing test, and the Church-Turing thesis, Jean Lassègue, and DPM.

On Alan Turing, also see SEP EB, ELC, Andrew Hodges, MMT, DPM.

type / token

A distinction, first drawn by Peirce, between signs considered as abstract things (types) or as particular instances (tokens). Thus, for example, the number of words (tokens) in this Dictionary—the "word-count" of its content—may be quite large, but the number of different words (types) it uses—the working vocabulary of its author—is surely much smaller.

The distinction is also used by Davidson and other philosophers of mind to emphasize that a reasonable identity theory need only argue for the identity of mental and physical events as types, not necessarily as tokens.

Also see SEP.

types, theory of

The solution proposed by Russell for the self-referential paradox that arises from the notion of "the class of all classes that are not members of themselves." Russell envisioned an indefinite hierarchy of types to be symbolized: ordinary objects; the properties and relations of ordinary objects; the features of properties of objects; etc.; etc. Defining each item by reference only to those of a lower type avoids paradox, but may not resolve every instance of difficulty with self-reference.

Recommended Reading: Irving M. Copi, The Theory of Logical Types (Routledge, 1971); Bertrand Russell, Introduction to Mathematical Philosophy (Dover, 1993); and Roy L. Crole, Categories for Types (Cambridge, 1994).

Also see SEP and a target="new" href="">EB.


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