Truth (Arthur Schopenhauer)
German philosopher Arthur Schopenhauer's 1818 final paragraph to the preface of the first edition of his two-volume magnum opus The World as Will and Representation, written only two years after consulting with Goethe, the origin of the famous "three stages of truth" quote. [4]
In science, truth is that which has the grand character of the capability of enduring the test of universal experience, and coming unchanged out of every possible form of fair discussion. [1]

Stages of truth
The following is the post 1981 truncated version of famous 1818 "three stages of truth" quote by German philosopher Arthur Schopenhauer: [4]

“All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.”

The quote comes from the final paragraph, 1958 English translation by E.F.J. Payne, shown adjacent bolded, of Schopenhauer's 1818 The World as Will and Representation:

“To truth only a brief celebration of victory is allowed between two long periods during which it is condemned as paradoxical, or disparaged as trivial.”

which outlines his Goethean philosophy human chemical theory based "will to power" philosophy. The original German is: [5]

“Der Wahrheit ist allerzeit nur ein kurzes Siegesfest beschieden, zwischen den beiden langen ZeitrÄaumen, wo sie als Paradox verdammt und als Trivial gering geschÄatzt wird.”

See the lecture article: HCT | Truth for more on the details behind this quote.

In 1963, English biochemist (chnopsological chemist) John Haldane, in commentary on a new book that has life tables that consistently overestimate future death rates, thus being favorable to life insurance companies but unfavorable to companies that pay life annuities to the aged, comments that the resistance to the process of acceptance of this new system of doing things will pass through the usual "four stages of resistance" to new ways of seeing things: [6]

1. This is worthless nonsense
2. This is an interesting, but perverse, point of view
3. This is true, but quite unimportant
4. I always said so

Quotes
The following are related quotes:

Plato is my friend, but truth my greater friend.”
Aristotle (c.300BC) [2]

“Fables should be taught as fables, myths as myths, and miracles as poetic fancies. To teach superstitions as truths is a most terrible thing. The child mind accepts and believes them, and only through great pain and perhaps tragedy can he be in after years relieved of them. In fact, men will fight for a superstition quite as quickly as for a living truth—often more so, since a superstition is so intangible you cannot get at it to refute it, but truth is a point of view, and so is changeable.”
Hypatia (c.400)

Life is an unfoldment, and the further we travel the more truth we can comprehend. To understand the things that are at our door is the best preparation for understanding those that lie beyond.”
Hypatia (c.400)

“Those who rely simply on the weight of authority to prove any assertion, without searching out the arguments to support it, act absurdly. I wish to question freely and to answer freely without any sort of adulation. That well becomes any who are sincere in the search for truth.”
— Vincenzo Galilei (c.1570)

“A thousand Demosthenes, a thousand Aristotles can be laid prostrate by a single man of mediocre talent who has seized upon a better way to find the truth. Such a hope, therefore, must be removed: for indeed, men, more learned and superior to us in book-learning, will be found who, to the same of nature itself, can make that which is, in fact, false, true.”
Galileo (1632), Dialogue on the Two Chief World Systems; cited by Otto Guericke (1672) in "Preface" to Magdeburg Experiments

“There is some truth in Boerhaave's poetic comparison: [that] [force of chemical affinity] is “love, if love be the desire for marriage”.
Jean Dumas (1837), commentary on Herman Boerhaave’s 1732 conjecture

“The first business of a man of science is to proclaim the truth as he finds it; and let the world adjust itself as best it can to the new knowledge.”
Percy Bridgman (469 PE) (1919), American thermodynamicist

“A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”
Max Planck (c.1947), on how Boltzmann's statistical thermodynamics and atomic hypothesis triumphed over those as Ernst Mach and others of the energetics school. [3]

“The second law of thermodynamics is one of the bedrock truth that physics offers to the world.”
Eric Zencey (1983), “Entropy as Root Metaphor” [7]

Truth does not demand belief. Scientists do not join hands every Sunday, singing, ‘yes, gravity is real! I will have faith! I will be strong! I believe in my heart that what goes up, up, up, must come down … Amen!’ If they did, we would think they were pretty insecure about it.”
— Dan Barker (c.2005) (Ѻ)

“The first rule of science is the truth at any price including the price of your life. That rule also applies to morality.”
Howard Bloom (2012), The God Problem: How a Godless Cosmos Creates

See also
True

References
1. (a) Quoted definition by John Herschel as cited by Karl Pearson.
(b) Pearson, Karl. (1900). The Grammar of Science (pg. 100). Adam and Charles Black.
2. Gleick, James. (2003). Isaac Newton (pg. 26). Vintage.
3. (a) Planck, Max. (1949). Scientific Autobiography, and Other Papers (pgs. 33-34). Trans. by Frank Gaynor. Philosophical Library.
(b) Hokikian, Jack. (2002). The Science of Disorder: Understanding the Complexity, Uncertainty, and Pollution in Our World (pg. 179). Los Feliz Publishing.
4. Schopenhauer, Arthur. (1818). The World as Will and Representation, Volume I (Elective Affinity, pgs. 110, 122, 148; truth quote, pg. xvii), trans. E.F.J. Payne. Dover, 1966.
5. (a) Shallit, Jeffrey. (2005). “Science, Pseudoscience, and the Three Stages of Truth”, University of Waterloo, Ontario.
(b) Attribution of Schopenhauer’s Three Stages of Truth – MetaBunk.org.
6. Haldane, J.B.S. (1963). “Book Review: The Truth About Death”. Journal of Genetics, Vol. 58:463-64.
7.Zencey, Eric. (1983). “Entropy as Root Metaphor”, Conference on Science, Technology, and Literature, Feb, Long Island University, New York; in: Beyond the Two Cultures: Essays on Science, Technology, and Literature (editors: Joseph Slade and Judith Lee) (§9:185-200; quote, pg. 189), Iowa State University Press, 1900.

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