In these matters the only certainty is that nothing is certain.
Pliny the Elder

Inquiry is fatal to certainty.
Will Durant

It has become a certainty now that if you will only advertise sufficiently you may make a fortune by selling anything.
Anthony Trollope

It is far better to foresee even without certainty than not to foresee at all.
Henri Poincare

It is only of life on Earth, however, that one can speak with any certainty. It seems to me that all life on Earth, the sum total of life upon the Earth, has purpose.
Clifford D. Simak

It is to be feared that those who emigrate to New South Wales, generally anticipate too great facility in their future operations and certainty of success in conducting them; but they should recollect that competency cannot be obtained without labour.
Charles Sturt

Jealousy lives upon doubts. It becomes madness or ceases entirely as soon as we pass from doubt to certainty.
Francois de La Rochefoucauld

Many slaves on this continent are oppressed, and their cries have reached the ears of the Most High. Such are the purity and certainty of his judgments, that he cannot be partial in our favor.
John Woolman

Mystery is gone to the certainty of technological principles. So the real terror, the real aggression against life comes in the form of the pursuit of our technological happiness.
Godfrey Reggio

No great deed is done by falterers who ask for certainty.
George Eliot

One must verify or expel his doubts, and convert them into the certainty of Yes or NO.
Thomas Carlyle

One thing, however, I know with certainty: violence, or the direct threat of violence, of the kind we have seen in the past few days, is totally unjustified as a response to any published word or image.
Timothy Garton Ash

Only a very bad theologian would confuse the certainty that follows revelation with the truths that are revealed. They are entirely different things.
Denis Diderot

Probability is expectation founded upon partial knowledge. A perfect acquaintance with all the circumstances affecting the occurrence of an event would change expectation into certainty, and leave nether room nor demand for a theory of probabilities.
George Boole

Psychologists have set about describing the true nature of women with a certainty and a sense of their own infallibility rarely found in the secular world.
Naomi Weisstein

Science has proof without any certainty. Creationists have certainty without any proof.
Ashley Montagu

Sooner or later you must move down an unknown road that leads beyond the range of the imagination, and the only certainty is that the trip has to be made.
Bruce Catton

Spending a weekend with Hitler would have been boring in the extreme, although you would have had a greater certainty in coming back alive.
Alan Bullock

Step by step a powerful and enterprising race has driven them back from the Atlantic to the West until at last there is scarcely a spot of ground upon which the Indians have any certainty of maintaining a permanent abode.
Nelson A. Miles

That though we are certain of many things, yet that Certainty is no absolute Infallibility, there still remains the possibility of our being mistaken in all matters of humane Belief and Inquiry.
Joseph Glanvill