[Regarding evolution believers:] Their business is not with the possible, but the actual—not with a world which might be, but with a world that is. This they explore with a courage not unmixed with reverence, and according to methods which, like the quality of a tree, are tested by their fruits. They have but one desire—to know the truth. They have but one fear—to believe a lie.

~~[Misattributed - NOT by Jefferson]~~ I am a great believer in Luck. The harder I work, the more of it I seem to have.

As far as I see, such a theory [of the primeval atom] remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being. He may keep, for the bottom of space-time, the same attitude of mind he has been able to adopt for events occurring in non-singular places in space-time. For the believer, it removes any attempt to familiarity with God, as were Laplace’s chiquenaude or Jeans’ finger. It is consonant with the wording of Isaiah speaking of the “Hidden God” hidden even in the beginning of the universe … Science has not to surrender in face of the Universe and when Pascal tries to infer the existence of God from the supposed infinitude of Nature, we may think that he is looking in the wrong direction.

As to the Christian religion, Sir, … there is a balance in its favor from the number of great men who have been convinced of its truth after a serious consideration of the question. Grotius was an acute man, a lawyer, a man accustomed to examine evidence, and he was convinced. Grotius was not a recluse, but a man of the world, who surely had no bias on the side of religion. Sir Isaac Newton set out an infidel, and came to be a very firm believer.

Both Religion and science require faith in God. For believers, God is in the beginning, and for physicists He is at the end of all considerations.

Collective unity is not the result of the brotherly love of the faithful for each other. The loyalty of the true believer is to the whole—the church, party, nation—and not to his fellow true believer. True loyalty between individuals is possible only in a loose and relatively free society.

Euler was a believer in God, downright and straightforward. The following story is told by Thiebault, in his Souvenirs de vingt ans de séjour à Berlin, … Thiebault says that he has no personal knowledge of the truth of the story, but that it was believed throughout the whole of the north of Europe. Diderot paid a visit to the Russian Court at the invitation of the Empress. He conversed very freely, and gave the younger members of the Court circle a good deal of lively atheism. The Empress was much amused, but some of her counsellors suggested that it might be desirable to check these expositions of doctrine. The Empress did not like to put a direct muzzle on her guest’s tongue, so the following plot was contrived. Diderot was informed that a learned mathematician was in possession of an algebraical demonstration of the existence of God, and would give it him before all the Court, if he desired to hear it. Diderot gladly consented: though the name of the mathematician is not given, it was Euler. He advanced toward Diderot, and said gravely, and in a tone of perfect conviction:
Monsieur, (a + bⁿ) / n = x, donc Dieu existe; repondez!
Diderot, to whom algebra was Hebrew, was embarrassed and disconcerted; while peals of laughter rose on all sides. He asked permission to return to France at once, which was granted.

His conflict with the Catholic Church arose because deep in his heart Galileo was a believer. There was for him no path of compromise, no way to have separate secular and theological cosmologies. If the Copernican system was true as he believed, what else could Galileo do but fight with every weapon he had in his arsenal of logic, rhetoric, scientific observation, mathematical theory, and cunning insight, to make his Church accept a new system of the universe?

I am a believer in unconscious cerebration. The brain is working all the time, though we do not know it. At night it follows up what we think in the daytime. When I have worked a long time on one thing, I make it a point to bring all the facts regarding it together before I retire; I have often been surprised at the results… We are thinking all the time; it is impossible not to think.

I am a firm believer in the theory that you can do or be anything that you wish in this world, within reason, if you are prepared to make the sacrifices, think and work hard enough and long enough.

I am a firm believer, that without speculation there is no good and original observation.

I am a great believer in Luck. The harder I work, the more of it I seem to have.

I am a great believer in the simplicity of things and as you probably know I am inclined to hang on to broad & simple ideas like grim death until evidence is too strong for my tenacity.

I am a hard-core believer that the clean desktop is the way to go…. At the same time, we told OEMs that if they were going to put a bunch of icons on the desktop, then so were we.

I am not, personally, a believer or a religious man in any sense of institutional commitment or practice. But I have a great respect for religion, and the subject has always fascinated me, beyond almost all others (with a few exceptions, like evolution and paleontology).

I understood that you would take the human race in the concrete, have exploded the absurd notion of Pope’s Essay on Man, [Erasmus] Darwin, and all the countless believers even (strange to say) among Christians of man’s having progressed from an ouran-outang state—so contrary to all History, to all religion, nay, to all possibility—to have affirmed a Fall in some sense as a fact….

It is certainly true in the United States that there is an uneasiness about certain aspects of science, particularly evolution, because it conflicts, in some people’s minds, with their sense of how we all came to be. But you know, if you are a believer in God, it’s hard to imagine that God would somehow put this incontrovertible evidence in front of us about our relationship to other living organisms and expect us to disbelieve it. I mean, that doesn't make sense at all.

Later scientific theories are better than earlier ones for solving puzzles in the often quite different environments to which they are applied. That is not a relativist's position, and it displays the sense in which I am a convinced believer in scientific progress.

My father, and the father of my father, pitched their tents here before me. … For twelve hundred years have the true believers—and, praise be to God! all true wisdom is with them alone—been settled in this country, and not one of them ever heard of a palace underground. Neither did they who went before them. But lo! here comes a Frank from many days’ journey off, and he walks up to the very place, and he takes a stick … and makes a line here, and makes a line there. Here, says he, is the palace; there, says he, is the gate; and he shows us what has been all our lives beneath our feet, without our having known anything about it. Wonderful! Wonderful! Is it by books, is it by magic, is it by your prophets, that you have learnt wisdom?

Rutherford was as straightforward and unpretentious as a physicist as he was elsewhere in life, and that no doubt was one of the secrets of his success. “I was always a believer in simplicity, being a simple man myself,” he said. If a principle of physics could not be explained to a barmaid, he insisted, the problem was with the principle, not the barmaid.

Scientists and particularly the professional students of evolution are often accused of a bias toward mechanism or materialism, even though believers in vitalism and in finalism are not lacking among them. Such bias as may exist is inherent in the method of science. The most successful scientific investigation has generally involved treating phenomena as if they were purely materialistic, rejecting any metaphysical hypothesis as long as a physical hypothesis seems possible. The method works. The restriction is necessary because science is confined to physical means of investigation and so it would stultify its own efforts to postulate that its subject is not physical and so not susceptible to its methods.

The believer has the whole world of wealth (Prov. 17: 6 LXX) and “possesses all things as if he had nothing” (2 Cor. 6: 10) by virtue of his attachment to you whom all things serve; yet he may know nothing about the circuits of the Great Bear. It is stupid to doubt that he is better than the person who measures the heaven and counts the stars and weighs the elements, but neglects you who have disposed everything “by measure and number and weight” (Wisd. 11: 21).

The bigotry of the nonbeliever is for me nearly as funny as the bigotry of the believer.

The desire for guidance, love, and support prompts men to form the social or moral conception of God. This is the God of Providence, who protects, disposes, rewards, and punishes; the God who, according to the limits of the believer’s outlook, loves and cherishes the life of the tribe or of the human race, or even or life itself; the comforter in sorrow and unsatisfied longing; he who preserves the souls of the dead. This is the social or moral conception of God.

The fact that stares one in the face is that people of the greatest sincerity and of all levels of intelligence differ and have always differed in their religious beliefs. Since at most one faith can be true, it follows that human beings are extremely liable to believe firmly and honestly in something untrue in the field of revealed religion. One would have expected this obvious fact to lead to some humility, to some thought that however deep one's faith, one may conceivably be mistaken. Nothing is further from the believer, any believer, than this elementary humility. All in his power … must have his faith rammed down their throats. In many cases children are indeed indoctrinated with the disgraceful thought that they belong to the one group with superior knowledge who alone have a private wire to the office of the Almighty, all others being less fortunate than they themselves.

There are two objectionable types of believers: those who believe the incredible and those who believe that 'belief' must be discarded and replaced by 'the scientific method'.