It is always better to ask then to make an assumption.
—Miguel Angel Ruiz (b.1952) Mexican Spiritualist Author
Good tests kill flawed theories; we remain alive to guess again.
—Karl Popper (1902–94) Austrian-born British Philosopher
A speculator is a man who observes the future, and acts before it occurs.
—Bernard M. Baruch (1870–1965) American Financier, Economic Consultant
Delight at having understood a very abstract and obscure system leads most people to believe in the truth of what it demonstrates.
—Georg Christoph Lichtenberg (1742–99) German Philosopher, Physicist
A theory is the more impressive the greater is the simplicity of its premises, the more different are the kinds of things it relates and the more extended the range of its applicability.
—Albert Einstein (1879–1955) German-born Physicist
Some theories are good for nothing except to be argued about.
—Georg Christoph Lichtenberg (1742–99) German Philosopher, Physicist
Socrates thought and so do I that the wisest theory about the gods is no theory at all.
—Michel de Montaigne (1533–92) French Essayist
Theories are always very thin and insubstantial, experience only is tangible.
—Hosea Ballou (1771–1852) American Theologian
There are two times in a man’s life when he shouldn’t speculate: when he can afford to and when he can’t.
—Mark Twain (1835–1910) American Humorist
Every State has a natural right in cases not within the compact casus non faederis to nullify of their own authority all assumptions of power by others within their limits. Without this right, they would be under the dominion, absolute and unlimited, of whosoever might exercise this right of judgment for them
—Thomas Jefferson (1743–1826) American Head of State, Lawyer
Even for practical purposes theory generally turns out the most important thing in the end.
—Oliver Wendell Holmes, Jr. (1841–1935) American Jurist, Author
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.
—A. J. Ayer (1910–89) English Philosopher
Unaware of the absurdity of it, we introduce our own petty household rules into the economy of the universe for which the life of generations, peoples, of entire planets, has no importance in relation to the general development.
—Alexander Herzen (1812–70) Russian Revolutionary, Writer
The world can doubtless never be well known by theory: practice is absolutely necessary; but surely it is of great use to a young man, before he sets out for that country, full of mazes, windings, and turnings, to have at least a general map of it, made by some experienced traveler.
—Earl of Chesterfield (1694–1773) English Statesman, Man of Letters
Treat with utmost respect your power of forming opinions, for this power alone guards you against making assumptions that are contrary to nature and judgments that overthrow the rule of reason.
—Marcus Aurelius (121–180) Emperor of Rome, Stoic Philosopher
I never guess. It is a shocking habit—destructive to the logical faculty.
—Arthur Conan Doyle (1859–1930) Scottish Writer
You must stick to your conviction, but be ready to abandon your assumptions.
—Denis Waitley (b.1933) American Motivational Speaker, Author
A conception not reducible to the small change of daily experience is like a currency not exchangeable for articles of consumption; it is not a symbol, but a fraud.
—George Santayana (1863–1952) Spanish-American Poet, Philosopher
The temptation to form premature theories upon insufficient data is the bane of our profession.
—Arthur Conan Doyle (1859–1930) Scottish Writer
No theory is good unless it permits, not rest, but the greatest work. No theory is good except on condition that one use it to go on beyond.
—Andre Gide (1869–1951) French Novelist
The way to keep yourself from making assumptions is to ask questions.
—Miguel Angel Ruiz (b.1952) Mexican Spiritualist Author
Most of our assumptions have outlived their uselessness.
—Marshall Mcluhan (1911–80) Canadian Writer, Thinker, Educator
We simply assume that the way we see things is the way they really are or the way they should be. And our attitudes and behaviors grow out of these assumptions.
—Stephen Covey (1932–2012) American Self-help Author
A young man is a theory, an old man is a fact.
—E. W. Howe (1853–1937) American Novelist, Editor
Let us work without theorizing, ‘Tis the only way to make life endurable.
—Voltaire (1694–1778) French Philosopher, Author
If the world were good for nothing else, it is a fine subject for speculation.
—William Hazlitt (1778–1830) English Essayist
Speculation is only a word covering the making of money out of the manipulation of prices, instead of supplying goods and services.
—Henry Ford (1863–1947) American Businessperson, Engineer
The world always makes the assumption that the exposure of an error is identical with the discovery of truth—that the error and truth are simply opposite. They are nothing of the sort. What the world turns to, when it is cured on one error, is usually simply another error, and maybe one worse than the first one.
—H. L. Mencken (1880–1956) American Journalist, Literary Critic
The wise man regulates his conduct by the theories both of religion and science. But he regards these theories not as statements of ultimate fact but as art-forms.
—J. B. S. Haldane (1892–1964) British Biologist, Geneticist
Creating a new theory is not like destroying an old barn and erecting a skyscraper in its place. It is rather like climbing a mountain, gaining new and wider views, discovering unexpected connections between our starting points and its rich environment. But the point from which we started out still exists and can be seen, although it appears smaller and forms a tiny part of our broad view gained by the mastery of the obstacles on our adventurous way up.
—Albert Einstein (1879–1955) German-born Physicist