Philosopher Quotes on Truth
The question of truth — what it is, how we recognize it, and whether it is one or many — has been central to philosophy since Parmenides. Classical correspondence theories hold that truth is agreement between thought and reality; coherence theories hold that truth is mutual fit among beliefs; pragmatist accounts tie truth to successful inquiry. Twentieth-century philosophers debated whether truth is a substantive property at all or a logical device for endorsing claims. The quotes collected here approach truth in moral, religious, and scientific registers.
812 philosophers in this collection have quotes tagged with truth, totalling 2249 quotes.
Wonhyo on Truth
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Attributed to Wonhyo:
“All things are made by the mind alone; outside the mind there is nothing to be sought.”
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Attributed to Wonhyo:
“The Buddha and the ordinary mind are not two; only the recognition of this is two.”
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Attributed to Wonhyo:
“Doctrines fight only when their followers do not yet understand.”
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Attributed to Wonhyo:
“What you take for a pure spring in the dark may be a skull in the morning; the spring is in your mind.”
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Attributed to Wonhyo:
“When mind arises, all things arise; when mind ceases, all things cease.”
John Stuart Mill on Truth
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“He who knows only his own side of the case knows little of that.”
Ch. II: Of the Liberty of Thought and Discussion -
“If all mankind minus one were of one opinion, mankind would be no more justified in silencing that one person than he, if he had the power, would be justified in silencing mankind.”
Ch. II: Of the Liberty of Thought and Discussion -
“We are not so absurd as to propose that the teacher should not set forth his own opinions as the true ones and exert his utmost powers to exhibit their truth in the strongest light. To abstain from this would be to nourish the worst intellectual habit of all, that of not finding, and not looking for, certainty in any teacher. But the teacher himself should not be held to any creed; nor should the question be whether his own opinions are the true ones, but whether he is well instructed in those of other people, and, in enforcing his own, states the arguments for all conflicting opinions fairly.”
Civilization," London and Westminster Review (April 1836) -
“All students of man and society who possess that first requisite for so difficult a study, a due sense of its difficulties, are aware that the besetting danger is not so much of embracing falsehood for true, as of mistaking part of the truth for the whole.”
Coleridge”. London and Westminster Review. (March 1840) -
Attributed to John Stuart Mill:
“All silencing of discussion is an assumption of infallibility.”
Karl Popper on Truth
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“We do not know: we can only guess.”
Ch. 10 "Corroboration, or How a Theory Stands up to Tests", section 85: The Path of Science, p. 278. -
“If we are uncritical we shall always find what we want: we shall look for, and find, confirmations.”
The Poverty of Historicism (1957) Ch. 29 The Unity of Method -
“Good tests kill flawed theories; we remain alive to guess again.”
As quoted in My Universe : A Transcendent Reality (2011) by Alex Vary, Part II -
“Science must begin with myths, and with the criticism of myths.”
Ch. 1 "Science : Conjectures and Refutations", Section VII -
“Scientists try to eliminate their false theories, they try to let them die in their stead. The believer—whether animal or man—perishes with his false beliefs.”
Epistemology Without A Knowing Subject (1967)
Charles Sanders Peirce on Truth
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“Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have. Then, our conception of these effects is the whole of our conception of the object.”
Vol. V, par. 438 -
“True science is distinctively the study of useless things. For the useful things will get studied without the aid of scientific men.”
Wikiquote -
Attributed to Charles Sanders Peirce:
“We must not begin by talking of pure ideas, vagabond thoughts that tramp the public roads without any human habitation, but must begin with men and their conversation.”
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Attributed to Charles Sanders Peirce:
“It seems a strange thing that a sign should leave its interpreter to supply a part of its meaning.”
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Attributed to Charles Sanders Peirce:
“The opinion which is fated to be ultimately agreed to by all who investigate, is what we mean by the truth.”
Susan Sontag on Truth
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“Interpretation is the revenge of the intellect upon art.”
p. 7 -
“Ours is an age which consciously pursues health , and yet only believes in the reality of sickness . The truths we respect are those born of affliction. We measure truth in terms of the cost to the writer in suffering — rather than by the standard of an objective truth to which a writer's words correspond. Each of our truths must have a martyr.”
Review of Selected Essays by Simone Weil , The New York Review of Books (1 February 1963) -
“The need for truth is not constant; no more than is the need for repose. An idea which is a distortion may have a greater intellectual thrust than the truth; it may better serve the needs of the spirit, which vary. The truth is balance, but the opposite of truth, which is unbalance, may not be a lie.”
Review of Selected Essays by Simone Weil , The New York Review of Books (1 February 1963) -
“The truth is always something that is told, not something that is known. If there were no speaking or writing, there would be no truth about anything. There would only be what is.”
The Benefactor (1963), Ch. 1, p. 1, Farrar, Straus and Giroux ISBN 0-312-42012-9 -
Attributed to Susan Sontag:
“To photograph is to appropriate the thing photographed.”
W. V. O. Quine on Truth
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“To be is to be the value of a variable.”
On What There Is -
Attributed to W. V. O. Quine:
“Our statements about the external world face the tribunal of sense experience not individually but only as a corporate body.”
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Attributed to W. V. O. Quine:
“Any statement can be held true come what may, if we make drastic enough adjustments elsewhere in the system.”
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Attributed to W. V. O. Quine:
“The myth of physical objects is epistemologically superior to most in that it has proved more efficacious than other myths as a device for working a manageable structure into the flux of experience.”
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Attributed to W. V. O. Quine:
“No entity without identity.”
Maimonides on Truth
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“[…] one should accept the truth from whatever source it proceeds.”
Foreword to The Eight Chapters Of Maimonides On Ethics , translated by Joseph I. Gorfinkle, Ph.D. Columbia University Press, New York (1912). Page 35-36 . | Variant: "Accept the truth from whatever source it comes." Introduction to the Shemonah Peraqim , as quoted in Truth and Compassion: Essays on Judaism and Religion in Memory of Rabbi Dr. Solomon Frank (1983) Edited by Howard Joseph, Jack Natha -
“Variant: "Accept the truth from whatever source it comes." Introduction to the Shemonah Peraqim , as quoted in Truth and Compassion: Essays on Judaism and Religion in Memory of Rabbi Dr. Solomon Frank (1983) Edited by Howard Joseph, Jack Nathan Lightstone, and Michael D. Oppenheim, p. 168”
[…] one should accept the truth from whatever source it proceeds. -
“Variant: You must accept the truth from whatever source it comes.”
[…] one should accept the truth from whatever source it proceeds. -
Attributed to Maimonides:
“Truth does not become more true by virtue of the fact that the entire world agrees with it, nor less so even if the whole world disagrees with it.”
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Attributed to Maimonides:
“Astrology is a disease, not a science.”
Nagarjuna on Truth
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Attributed to Nagarjuna:
“Nothing whatsoever has ever existed in itself.”
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Attributed to Nagarjuna:
“Whatever is dependently co-arisen, that is explained to be emptiness.”
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Attributed to Nagarjuna:
“Samsara is nothing essentially different from nirvana; nirvana is nothing essentially different from samsara.”
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Attributed to Nagarjuna:
“Without dependence on conventional truth, the meaning of the ultimate cannot be taught.”
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Attributed to Nagarjuna:
“If I had any thesis, that fault would apply to me; but I have no thesis at all.”
Adi Shankara on Truth
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“Brahman (the existential substratum) is the only truth, the world is illusion, and there is ultimately no difference between Brahman and individual self.”
Brahma satyam jagat mithyam, jivo brahmaiva naparah -
“When the force of desire for the Truth blossoms, selfish desires wither away, just like darkness vanishes before the radiance of the light of dawn.”
P4 -
Attributed to Adi Shankara:
“Brahman alone is real; the world is illusory; the individual self is non-different from Brahman.”
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Attributed to Adi Shankara:
“Pleasure and pain are mere ideas, transient and unreal; renounce them.”
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Attributed to Adi Shankara:
“He who sees all beings in the Self and the Self in all beings has no fear.”
D. T. Suzuki on Truth
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“The Mahayana Buddhists offer a doctrine complementary to that of karma, in order to give a more satisfying and more human solution to our inmost religious needs. The Mahayana doctrine of Parinamana , therefore, must go side by side with that of karma; for through this harmonious co-working of the two, the true spirit of Buddhism will be more effectively realized. In this phase of development, Mahayana Buddhism must be said to be profoundly religious.”
p 9 -
Attributed to D. T. Suzuki:
“Zen, in its essence, is the art of seeing into the nature of one's own being.”
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Attributed to D. T. Suzuki:
“If you have a glass full of liquid, you can discourse forever on its qualities, but until you drink it, you cannot know its taste.”
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Attributed to D. T. Suzuki:
“The truth of Zen is not in any of its statements, however profound; it is in life itself.”
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Attributed to D. T. Suzuki:
“We are too self-conscious, too logical, and we lose touch with the underlying reality of our own being.”
F. H. Bradley on Truth
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“Metaphysics is the finding of bad reasons for what we believe upon instinct, but to find these reasons is no less an instinct.”
Appearance and Reality , preface (1893). -
“Eclecticism. Every truth is so true that any truth must be false.”
No. 6. -
“True penitence condemns to silence. What a man is ready to recall he would be willing to repeat.”
No. 10. -
Attributed to F. H. Bradley:
“Where everything is bad it must be good to know the worst.”
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Attributed to F. H. Bradley:
“The Absolute is one system, and its contents are nothing but sentient experience.”
Galileo Galilei on Truth
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“In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.”
sì perché l'autorità dell'opinione di mille nelle scienze non val per una scintilla di ragione di un solo, sì perché le presenti osservazioni spogliano d'autorità i decreti de' passati scrittori, i quali se vedute l'avessero, avrebbono diversamente determinato. -
“It seems to me that it was well said by Madama Serenissima, and insisted on by your reverence, that the Holy Scripture cannot err, and that the decrees therein contained are absolutely true and inviolable. But I should have in your place added that, though Scripture cannot err, its expounders and interpreters are liable to err in many ways ; and one error in particular would be most grave and most frequent, if we always stopped short at the literal signification of the words.”
Wikiquote -
Attributed to Galileo Galilei:
“Philosophy is written in this grand book, the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and read the letters in which it is composed. It is written in the language of mathematics.”
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Attributed to Galileo Galilei:
“All truths are easy to understand once they are discovered; the point is to discover them.”
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Attributed to Galileo Galilei:
“And yet it moves.”
Giordano Bruno on Truth
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“The universe is, then, one, infinite, immobile.”
As translated by Paul Harrison -
“If it is not true it is very well invented.”
Se non è vero, è molto ben trovato. -
“Variant translations: If it is not true, it is well conceived. If it is not true, it is a good story.”
Se non è vero, è molto ben trovato. -
Attributed to Giordano Bruno:
“Truth does not change because it is, or is not, believed by a majority of the people.”
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Attributed to Giordano Bruno:
“Perhaps you, my judges, pronounce this sentence against me with greater fear than I receive it.”
Gottlob Frege on Truth
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“Every good mathematician is at least half a philosopher, and every good philosopher is at least half a mathematician.”
Attributed to Frege in: A. A. B. Aspeitia (2000), Mathematics as grammar: 'Grammar' in Wittgenstein's philosophy of mathematics during the Middle Period , Indiana University, p. 25 -
Attributed to Gottlob Frege:
“Never ask for the meaning of a word in isolation, but only in the context of a proposition.”
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Attributed to Gottlob Frege:
“The laws of truth are not psychological laws.”
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Attributed to Gottlob Frege:
“A statement of number contains an assertion about a concept.”
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Attributed to Gottlob Frege:
“Thoughts are objective; they are neither things in the external world nor ideas in the mind.”
Hans-Georg Gadamer on Truth
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“The real being of language is what is said in it.”
Man and Language (1966) -
“The hermeneutic consciousness, which must be awakened and kept awake, recognizes that in the age of science philosophy's claim of superiority has something chimerical and unreal about it. But though the will of man is more than ever intensifying its criticism of what has gone before to the point of becoming a utopian or eschatological consciousness, the hermeneutic consciousness seeks to confront that will with something of the truth of remembrance: with what is still and ever again real.”
Foreword to the Second Edition, p. xxiv -
Attributed to Hans-Georg Gadamer:
“All understanding is interpretation.”
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Attributed to Hans-Georg Gadamer:
“Language is the medium in which substantive understanding and agreement take place between two people.”
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Attributed to Hans-Georg Gadamer:
“Prejudices are not necessarily unjustified and erroneous, so that they inevitably distort the truth.”
Hilary Putnam on Truth
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“These papers are all written from what is called a realist perspective. The statements of science are in my view either true or false (although it is often the case that we don't know which) and their truth or falsity does not consist in their being highly derived ways of describing regularities in human experience. Reality is not a part of the human mind; rather the human mind is a part - and a small part at that - of reality.”
Introduction: Science as approximation to truth -
“Introduction: Science as approximation to truth”
These papers are all written from what is called a realist perspective. The statements of science are in my view either true or false (although it is often the case that we don't know which) and their truth or falsity does not consist in their being highly derived ways of describing regularities in human experience. Reality is not a part of the human mind; rather the human mind is a part - and a s -
“Introduction: Science as approximation to truth”
If the importance of science does not lie in its constituting the whole of human knowledge, even less does it lie, in my view, in its technological applications. Science at the best is a way of coming to know, and hopefully a way of acquiring some reverence for, the wonders of nature. The philosophical study of science, at the best, has always been a way of coming to understand both some of the na -
“In closing, I can only apologize for not having given any positive account of either mathematical truth or mathematical necessity. I can only say that I have not given such an account because I think that the search for such an account is a fundamental mistake. It is not that there is nothing special about mathematics; it is that, in my opinion, the investigation of mathematics must presuppose and not seek to account for the truth of mathematics. But this is the beginning of another paper and not the end of this one.”
Truth and necessity in mathematics" (1964) -
“Truth and necessity in mathematics" (1964)”
In closing, I can only apologize for not having given any positive account of either mathematical truth or mathematical necessity. I can only say that I have not given such an account because I think that the search for such an account is a fundamental mistake. It is not that there is nothing special about mathematics; it is that, in my opinion, the investigation of mathematics must presuppose and
Isaac Newton on Truth
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“If I have seen further it is by standing on the shoulders of giants.”
If I have seen further it is by standing on ye sholders of Giants . -
“Plato is my friend, Aristotle is my friend, but my greatest friend is truth.”
Amicus Plato — amicus Aristoteles — magis amica veritas -
“Truth is ever to be found in simplicity, and not in the multiplicity and confusion of things.”
Cited in Rules for methodizing the Apocalypse , Rule 9, from a manuscript published in The Religion of Isaac Newton (1974) by Frank E. Manuel, p. 120, as quoted in Socinianism And Arminianism : Antitrinitarians, Calvinists, And Cultural Exchange in Seventeenth-Century Europe (2005) by Martin Mulsow, Jan Rohls, p. 273. | Variant: Truth is ever to be found in the simplicity, and not in the multiplic -
“This is a variation on a much older adage, which Roger Bacon attributed to Aristotle : Amicus Plato sed magis amica veritas . Bacon was perhaps paraphrasing a statement in the Nicomachean Ethics : Where both are friends, it is right to prefer truth.”
Amicus Plato — amicus Aristoteles — magis amica veritas -
Attributed to Isaac Newton:
“I do not feign hypotheses.”
Jean-Francois Lyotard on Truth
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“I define postmodern as incredulity toward metanarratives.”
p. xxiv -
“Let us wage a war on totality; let us be witnesses to the unpresentable.”
p.82 -
“Science has always been in conflict with narratives. Judged by the yardstick of science, the majority of them prove to be fables. But to the extent that science does not restrict itself to stating useful regularities and seeks truth, it is obliged to legitimate the rules of its own game.”
xxii -
“True knowledge, in this perspective, is always indirect knowledge; it is composed of reported statements, that are incorporated into metanarratives of a subject that source their legitimacy.”
p.35 -
Attributed to Jean-Francois Lyotard:
“There is no language in general.”
Karl Jaspers on Truth
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“On Truth (1948), Pt 2, Ch. 3, II, B, 3, b)”
The interlacedness of the two heterogeneous origins [Remark: This refers to the origins of governance: (1) necessity to work cooperatively, (2) the fight between man and man] prevails as the fundamental characteristic of governance. Therefore even any true community, being successful somewhere between boundaries for a common purpose, elsewhere becomes in theory a means for misleading, used to inte -
“The Greek word for philosopher ( philosophos ) connotes a distinction from sophos . It signifies the lover of wisdom (knowledge) as distinguished from him who considers himself wise in the possession of knowledge . This meaning of the word still endures: the essence of philosophy is not the possession of the truth but the search for truth. … Philosophy means to be on the way. Its questions are more essential than its answers , and every answer becomes a new question.”
Way to Wisdom: An Introduction to Philosophy (1951) as translated by Ralph Mannheim , Ch. 1, What is Philosophy?, p. 12 | Variant translation: It is the search for the truth , not possession of the truth which is the way of philosophy. Its questions are more relevant than its answers, and every answer becomes a new question. -
“Variant translation: It is the search for the truth , not possession of the truth which is the way of philosophy. Its questions are more relevant than its answers, and every answer becomes a new question.”
The Greek word for philosopher ( philosophos ) connotes a distinction from sophos . It signifies the lover of wisdom (knowledge) as distinguished from him who considers himself wise in the possession of knowledge . This meaning of the word still endures: the essence of philosophy is not the possession of the truth but the search for truth. … Philosophy means to be on the way. Its questions are mor -
Attributed to Karl Jaspers:
“Truth begins with two.”
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Attributed to Karl Jaspers:
“Communication is the unique value of philosophical life.”
Parmenides on Truth
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“You must learn all things, both the unshaken heart of persuasive truth , and the opinions of mortals in which there is no true warranty.”
Frag B 1.28-30, quoted by Sextus Empiricus , Against the Mathematicians , vii. 3; Simplicius , Commentary on the Heavens , 557-8; Proclus , Commentary on the Timaeus I , 345 -
“The only roads of enquiry there are to think of: one, that it is and that it is not possible for it not to be, this is the path of persuasion (for truth is its companion); the other, that it is not and that it must not be — this I say to you is a path wholly unknowable.”
Frag. B 2.2-6, quoted by Proclus , Commentary on the Timaeus I , 345 -
Attributed to Parmenides:
“It is the same thing to think and to be.”
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Attributed to Parmenides:
“What is, is; what is not, is not.”
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Attributed to Parmenides:
“It is necessary to speak and to think what is; for being is, but nothing is not.”
Ramana Maharshi on Truth
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“Who am I?”
Self-Inquiry -
“True silence is really endless speech.”
Wikiquote -
“Forgetfulness of your real nature is true death; remembrance of it is rebirth”
Wikiquote -
Attributed to Ramana Maharshi:
“All that is required to realize the Self is to be still.”
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Attributed to Ramana Maharshi:
“Silence is the highest form of teaching.”
Richard Rorty on Truth
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“On James's view, "true" resembles "good" or "rational" in being a normative notion, a compliment paid to sentences that seem to be paying their way and that fit with other sentences which are doing so.”
Introduction to Consequences of Pragmatism (1982) -
“Introduction to Objectivity, Relativism, and Truth: Philosophical Papers, Volume I (1991).”
My principal motive is the belief that we can still make admirable sense of our lives even if we cease to have … "an ambition of transcendence. -
“Introduction to Truth and Progress: Philosophical Papers, Volume 3 (1998).”
As long as we try to project from the relative and conditioned to the absolute and unconditioned, we shall keep the pendulum swinging between dogmatism and skepticism. The only way to stop this increasingly tiresome pendulum swing is to change our conception of what philosophy is good for. But that is not something which will be accomplished by a few neat arguments. It will be accomplished, if it -
“Introduction to Truth and Progress: Philosophical Papers, Volume 3 (1998).”
Philosophy makes progress not by becoming more rigorous but by becoming more imaginative. -
“John Searle on Realism and Relativism." Truth and Progress: Philosophical Papers, Volume 3 (1998).”
Truthfulness under oath is, by now, a matter of our civic religion, our relation to our fellow citizens rather than our relation to a nonhuman power.
Samuel Taylor Coleridge on Truth
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“The dwarf sees farther than the giant when he has the giant's shoulder to mount on.”
No. 15 (November 30, 1809), p. 228 | Cf. Isaac Newton , letter to Robert Hooke (15 February 1676): "If I have seen further it is only by standing on the shoulders of giants". -
Attributed to Samuel Taylor Coleridge:
“Imagination is the living power and prime agent of all human perception.”
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Attributed to Samuel Taylor Coleridge:
“He who begins by loving Christianity better than truth will end by loving himself better than all.”
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Attributed to Samuel Taylor Coleridge:
“Reason is the power of universal and necessary convictions.”
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Attributed to Samuel Taylor Coleridge:
“No man was ever yet a great poet, without being at the same time a profound philosopher.”
William of Ockham on Truth
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“Plurality is not to be posited without necessity.”
Numquam ponenda est pluralitas sine necessitate -
“It is vain to do with more what can be done with fewer.”
Frustra fit per plura, quod potest fieri per pauciora. -
“Intuitive cognition is such that when some things are cognized, of which one inheres in the other, or one is spatially distant from the other, or exists in some relation to the other, immediately in virtue of that non-propositional cognition of those things, it is known if the thing inheres or does not inhere, if it is spatially distant or not, and the same for other true contingent propositions, unless that cognition is flawed or there is some impediment.”
Opera Theologica (1986), edited by Gedeon Gal, Vol. I, p. 31. -
“It is on account of theology alone that any assertion whatsoever should be called catholic or heretical. For only an assertion which is consonant with theology is truly catholic, and only one which is known to be opposed to theology is known to be heretical. For if some assertion were found to be opposed to decrees of the highest pontiffs, or also of general councils or also to laws of the emperors, nevertheless, if it were not in conflict with theology, even if it could be considered false, erroneous or unjust, it should not be counted as a heresy.”
Vol. I, Book 1, Ch. 2 , as translated by John Kilcullen and John Scott (2003). -
Attributed to William of Ockham:
“Nothing is to be posited as necessary in nature unless it is established either by self-evidence, or by experience, or by the authority of Sacred Scripture.”
A. J. Ayer on Truth
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“There never comes a point where a theory can be said to be true . The most that one can claim for any theory is that it has shared the successes of all its rivals and that it has passed at least one test which they have failed.”
Philosophy in the Twentieth Century (1982) p. 133. -
Attributed to A. J. Ayer:
“No statement which refers to a reality transcending the limits of all possible sense-experience can have any literal significance.”
-
Attributed to A. J. Ayer:
“The presence of an ethical symbol in a proposition adds nothing to its factual content.”
-
Attributed to A. J. Ayer:
“There are no moral truths, but only moral attitudes.”
-
Attributed to A. J. Ayer:
“I tend to think that art expresses what cannot be put into theoretical form.”
More philosophers on Truth
- Alain Badiou
- Antony Flew
- Bhartrihari
- C. D. Broad
- C. I. Lewis
- Cratylus
- Daniel Dennett
- Derek Parfit
- Donald Davidson
- Emanuele Severino
- Ernest Nagel
- Ferdinand de Saussure
- Frank Ramsey
- Friedrich Kittler
- George Boole
- Gianni Vattimo
- Gorgias
- Hans Reichenbach
- Hans Urs von Balthasar
- Imre Lakatos
- J. L. Austin
- Jean Baudrillard
- Johann Georg Hamann
- John Calvin
- John Toland
- Karl Mannheim
- Kazimierz Ajdukiewicz
- Kukai
- Kurt Godel
- Linji Yixuan
- Luigi Pareyson
- Nishitani Keiji
- Paul Feyerabend
- Rudolf Carnap
- Sidney Hook
- Susan Stebbing
- Theodore Parker
- Thomas Kuhn
- Umberto Eco
- Walter Kaufmann
- William Whewell
- Alfred Tarski
- Ananda Coomaraswamy
- Bernard Williams
- Philolaus
- Melissus of Samos
- Pierre Duhem
- John McTaggart
- Mary Hesse
- Victor Cousin
- Michael Dummett
- Paul Ricoeur
- Ralph Cudworth
- Saul Kripke
- Alexandre Koyre
- Eusebius of Caesarea
- Giambattista Vico
- Ibn al-Haytham
- Norman Malcolm
- Christian Wolff
- David Lewis
- Dignaga
- Mikhail Bakhtin
- Bas van Fraassen
- F. C. S. Schiller
- Gillian Rose
- John Mackie
- David Strauss
- A. N. Prior
- Albrecht Wellmer
- Antoine Arnauld
- Aron Gurwitsch
- Bernard Bolzano
- Brand Blanshard
- Buddhapalita
- Candrakirti
- Carl Hempel
- Charles Stevenson
- D. M. Armstrong
- Diodorus Cronus
- Eduardo Nicol
- Eubulides of Miletus
- Francesco Patrizi
- Friedrich Adolf Trendelenburg
- Gilbert of Poitiers
- Hans Albert
- Hedwig Conrad-Martius
- Hermann Lotze
- Hippasus of Metapontum
- Jaakko Hintikka
- Jan Lukasiewicz
- John Findlay
- Karl-Otto Apel
- Kit Fine
- Lucien Goldmann
- Mary Shepherd
- Nelson Goodman
- Nicholas of Autrecourt
- Pavel Florensky
- Roy Wood Sellars
- Ruth Barcan Marcus
- Stanislaw Lesniewski
- Wesley Salmon
- Wilfrid Sellars
- Wilhelm Windelband
- William Wollaston
- William of Auvergne
- Rene Descartes
- Bertrand Russell
- Francis Bacon
- Ludwig Wittgenstein
- Gilles Deleuze
- Albert Einstein
- Leo Tolstoy
- Rumi
- Charles Darwin
- Jacques Maritain
- Louis Althusser
- Roland Barthes
- Al-Biruni
- Carl Schmitt
- Charles Hartshorne
- Claude Levi-Strauss
- Edward Caird
- Ernst Mach
- Etienne Gilson
- Friedrich Schlegel
- Gaston Bachelard
- Henri Poincare
- Honen
- Jean Wahl
- John Hick
- John Scotus Eriugena
- John Wyclif
- Joseph Albo
- Joseph Glanvill
- Justin Martyr
- Leszek Kolakowski
- Leucippus
- Madhva
- Martin Luther
- Michael Polanyi
- Mir Damad
- Nicholas Oresme
- Novalis
- Paul Tillich
- Robert Boyle
- Roger Bacon
- Simplicius
- Slavoj Zizek
- Sri Ramakrishna
- Susan Haack
- Tertullian
- Thomas Huxley
- Thomas Reid
- Vatsyayana
- William Ellery Channing
- William Hamilton
- Eisai
- G. E. Moore
- Pierre Bayle
- Aryadeva
- Edmund Husserl
- Ibn Arabi
- Karl Lowith
- P. F. Strawson
- Stanley Cavell
- Alexis Kagame
- Adelard of Bath
- Emile Boutroux
- Hakuin Ekaku
- Gershom Scholem
- Macrobius
- Peter Ramus
- Stephen Toulmin
- Al-Kindi
- Franz Rosenzweig
- Franz Brentano
- Helen Longino
- Peter Geach
- Jean le Rond d'Alembert
- Samuel Clarke
- Zhiyi
- Abe Masao
- Adolf Reinach
- Agrippa the Skeptic
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