109+ Best Louis Pasteur Quotes: Exclusive Selection

Louis Pasteur was a French biologist, microbiologist and chemist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization. He is remembered for his remarkable breakthroughs in the causes and prevention of diseases, and his discoveries have saved many lives ever since. He was one of the most important founders of medical microbiology. Inspirational Louis Pasteur quotes will encourage growth in life, make you wiser and broaden your perspective.

Most Famous Louis Pasteur Quotes

The more I study nature, the more I stand amazed at the work of the Creator. Science brings men nearer to God. – Louis Pasteur

Wine is the most healthful and most hygienic of beverages. – Louis Pasteur

Do not put forward anything that you cannot prove by experimentation. – Louis Pasteur

There are no such things as applied sciences, only applications of science. – Louis Pasteur

What did you do today to receive your instruction? – Louis Pasteur

Bernard was right. The germ is nothing, the terrain is everything. – Louis Pasteur

If science has no country, the scientist should have one, and ascribe to it the influence which his works may have in this world. – Louis Pasteur

Time is the best appraiser of scientific work, and I am aware that an industrial discovery rarely produces all its fruit in the hands of its first inventor. – Louis Pasteur

Chance favours the trained mind. – Louis Pasteur

The greatest disorder of the mind is to let will direct it. – Louis Pasteur

You have not succeeded in your experiments, that is all there is to it. – Louis Pasteur

Luck favors the mind that is prepared. – Louis Pasteur

To demonstrate experimentally that a microscopic organism actually is the cause of a disease and the agent of contagion, I know no other way, in the present state of Science, than to subject the microbe (the new and happy term introduced by M. Sédillot) to the method of cultivation out of the body. – Louis Pasteur

God grant that by my persevering labours I may bring a little stone to the frail and ill-assured edifice of our knowledge of those deep mysteries of Life and Death where all our intellects have so lamentably failed. – Louis Pasteur

Whatever your career may be, do not let yourselves become tainted by a deprecating and barren scepticism. – Louis Pasteur

By chance you will say, but chance only favors the mind which is prepared. – Louis Pasteur

If perchance you should falter during the journey, a hand would be there to support you. If that should be wanting, God, who alone could take that hand from you, would Himself accomplish its work. – Louis Pasteur

The grandeur of the acts of men are measured by the inspiration from which they spring. – Louis Pasteur

Science advances through tentative answers to a series of more and more subtle questions which reach deeper and deeper into the essence of natural phenomena. – Louis Pasteur

There are two men in each one of us: the scientist, he who starts with a clear field and desires to rise to the knowledge of Nature through observations, experimentation and reasoning, and the man of sentiment, the man of belief, the man who mourns his dead children, and who cannot, alas, prove that he will see them again, but who believes that he will, and lives in the hope – the man who will not die like a vibrio, but who feels that the force that is within him cannot die. – Louis Pasteur

There does not exist a category of science to which one can give the name applied science. There are sciences and the applications of science, bound together as the fruit of the tree which bears it. – Louis Pasteur

Outsidetheir laboratories, thephysicianand chemist are soldiers without arms on the field of battle. – Louis Pasteur

These microscopic organisms form an entire world composed of species, families and varieties whose history, which has barely begun to be written, is already fertile in prospects and findings of the highest importance. The names of these organisms are very numerous and will have to be defined and in part discarded. The word microbe which has the advantage of being shorter and carrying a more general meaning, and of having been approved by my illustrious friend, M. Littré, the most competent linguist in France, is one we will adopt. – Louis Pasteur

There is a time in every man’s life when he looks to his God, when he looks at his life, when he wonders how he will be remembered. – Louis Pasteur

Fortune favors the well-prepared. – Louis Pasteur

Do not let yourself be tainted with a barren skepticism. – Louis Pasteur

Live in the serene peace of laboratories and libraries – Louis Pasteur

If it is a terrifying thought that life is at the mercy of the multiplication of these minute bodies [microbes], it is a consoling hope that Science will not always remain powerless before such enemies. – Louis Pasteur

It is surmounting difficulties that makes heroes. – Louis Pasteur

Do not promote what you can’t explain, simplify, and prove early. – Louis Pasteur

My strength lies solely in my tenacity. – Louis Pasteur

Will opens the door to success, both brilliant and happy. – Louis Pasteur

Science brings men nearer to God. – Louis Pasteur

The controls of life are structured as forms and nuclear arrangements, in a relation with the motions of the universe. – Louis Pasteur

When you believe you have found an important scientific fact, and are feverishly curious to publish it, constrain yourself for days, weeks, years sometimes, fight yourself, try and ruin your own experiments, and only proclaim your discovery after having exhausted all contrary hypotheses. But when, after so many efforts you have at last arrived at a certainty, your joy is one of the greatest which can be felt by a human soul. – Louis Pasteur

Blessed is he who carries within himself a God, an ideal, and obeys it. – Louis Pasteur

Whether our efforts are, or not, favored by life, let us be able to say, when we come near to the great goal, I have done what I could. – Louis Pasteur

Where are the real sources of human dignity, freedom and modern democracy, if not in the concept of infinity to which all men are equal? – Louis Pasteur

Oh my goodness the mystery that has prompted my objective. My quality lies exclusively in my tirelessness. – Louis Pasteur

How do you know that the incessant progress of science will not compel scientists to consider that life has existed during eternity, and not matter? – Louis Pasteur

Virulence appears in a new light which cannot but be alarming to humanity; unless nature, in her evolution down the ages (an evolution which, as we now know, has been going on for millions, nay, hundreds of millions of years), has finally exhausted all the possibilities of producing virulent or contagious diseases – which does not seem very likely. – Louis Pasteur

The flavor of wine is like delicate poetry. – Louis Pasteur

Imagination should give wings to our thoughts but we always need decisive experimental proof, and when the moment comes to draw conclusions and to interpret the gathered observations, imagination must be checked and documented by the factual results of the experiment. – Louis Pasteur

Little science takes you away from God but more of it takes you to Him. – Louis Pasteur

To know how to wonder and question is the first step of the mind toward discovery. – Louis Pasteur

Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity. – Louis Pasteur

“Messieurs, c’est les microbes qui auront le dernier mot.”” (Gentlemen, it is the microbes who will have the last word.)” – Louis Pasteur

One does not ask of one who suffers: What is your country and what is your religion? One merely says: You suffer, that is enough for me. – Louis Pasteur

The role of the infinitely small in nature is infinitely great. – Louis Pasteur

A bottle of wine contains more philosophy than all the books in the world. – Louis Pasteur

Question your priorities often, make sure God always comes first. – Louis Pasteur

Inspiration is the impact of a fact on a well-prepared mind – Louis Pasteur

It is not the germs we need worry about. It is our inner terrain. – Louis Pasteur

Posterity will one day laugh at the sublime foolishness of the modern materialistic philosophy. The more I study nature, the more I stand amazed at the work of the Creator. I pray while I am engaged at my work in the laboratory. – Louis Pasteur

When I approach a child, he inspires in me two sentiments; tenderness for what he is, and respect for what he may become. – Louis Pasteur

Change only favours minds that are diligently looking and preparing for discovery. – Louis Pasteur

Where observation is concerned, chance favors only the prepared mind. – Louis Pasteur

The Greeks bequeathed to us one of the most beautiful words in our language–the word ‘enthusiasm’–en theos–a god within. The grandeur of human actions is measured by the inspiration from which they spring. Happy is he who bears a god within, and who obeys it. – Louis Pasteur

Life comes only from life. – Louis Pasteur

These three things-work, will, success-fill human existences. Will opens the door to success, both brilliant and happy. Work passes these doors, and at the end of the journey success comes in to crown one’s efforts. – Louis Pasteur

Intuition is given only to him who has undergone long preparation to receive it. – Louis Pasteur

Preconceived ideas are like searchlights which illumine the path of the experimenter and serve him as a guide to interrogate nature. They become a danger only if he transforms them into fixed ideas-this is why I should like to see these profound words inscribed on the threshold of all the temples of science: ‘The greatest derangement of the mind is to believe in something because one wishes it to be so.’ – Louis Pasteur

Science is the highest personification of the nation because that nation will remain the first which carries the furthest the works of thought and intelligence. – Louis Pasteur

The universe is asymmetric and I am persuaded that life, as it is known to us, is a direct result of the asymmetry of the universe or of its indirect consequences. The universe is asymmetric. Acknowledging the role of molecules that have stereoisomers, some the mirror image of the others, and microorganisms whose chemistry prefers only one of those forms. – Louis Pasteur

One must work; one must work. I have done what I could. – Louis Pasteur

Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment. – Louis Pasteur

Worship the spirit of criticism. – Louis Pasteur

Science proceeds by successive answers to questions more and more subtle, coming nearer and nearer to the very essence of phenomena. – Louis Pasteur

No, there is now no circumstance known in which it can be affirmed that microscopic beings came into the world without germs, without parents similar to themselves. Those who affirm it have been duped by illusions, by ill-conducted experiments, spoilt by errors that they either did not perceive or did not know how to avoid. – Louis Pasteur

It would seem to me that I was committing a theft if I were to let one day go by without doing some work. – Louis Pasteur

I have the faith of a Breton peasant and by the time I die I hope to have the faith of a Breton peasant’s wife. – Louis Pasteur

Work usually follows will. – Louis Pasteur

Analogy cannot serve as proof. – Louis Pasteur

I propose to provide proof… that just as always an alcoholic ferment, the yeast of beer, is found where sugar is converted into alcohol and carbonic acid, so always a special ferment, a lactic yeast, is found where sugar is transformed into lactic acid. And, furthermore, when any plastic nitrogenated substance is able to transform sugar into that acid, the reason is that it is a suitable nutrient for the growth of the [lactic] ferment. – Louis Pasteur

Are the atoms of the dextroacid (tartaric) grouped in the spirals of a right-hand helix or situated at the angles of an irregular tetrahedron, or arranged in such or such particular unsymmetrical fashion? We are unable to reply to these questions. But there can be no reason for doubting that the grouping of the atoms has an unsymmetrical arrangement with a non-superimposable image. It is not less certain that the atoms of the laevo-acid realize precisely an unsymmetrical arrangement of the inverse of the above. – Louis Pasteur

The only thing that can bring joy is work. – Louis Pasteur

We affirm the neutrality of Science … Science is of no country. … But if Science has no country, the scientist must keep in mind all that may work towards the glory of his country. In every great scientist will be found a great patriot. – Louis Pasteur

You bring me the deepest joy that can be felt by a man whose invincible belief is that Science and Peace will triumph over Ignorance and War, that nations will unite, not to destroy, but to build, and that the future will belong to those who will have done most for suffering humanity. – Louis Pasteur

In matters of observation chance favors only the prepared mind. (not literal translation) – Dan’s les champs de observation le hasard ne favorise que les esprits prepares. – Louis Pasteur

As in the experimental sciences, truth cannot be distinguished from error as long as firm principles have not been established through the rigorous observation of facts. – Louis Pasteur

The artificial products do not have any molecular dissymmetry; and I could not indicate the existence of a more profound separation between the products born under the influence of life and all the others. – Louis Pasteur

My present and most fixed opinion regarding the nature of alcoholic fermentation is this: The chemical act of fermentation is essentially a phenomenon correlative with a vital act, beginning and ending with the latter. I believe that there is never any alcoholic fermentation without their being simultaneously the organization, development, multiplication of the globules, or the pursued, continued life of globules which are already formed. – Louis Pasteur

It is a matter of fact; I approached without a preconceived idea, too ready to declare, if the experiment had imposed upon me the confession, that there was a spontaneous generation, of which I am convinced today that those who assure it are blindfolded. – Louis Pasteur

One must not assume that an understanding of science is present in those who borrow the language – Louis Pasteur

To bring one’s self to believe in a truth that has just dawned upon one is the first step towards progress; to persuade others is the second. – Louis Pasteur

There is no such thing as applied science, only the application of pure science. – Louis Pasteur

In the realm of scientific observation, luck is granted only to those who are prepared. – Louis Pasteur

If you suppress laboratories, physical science will be stricken with barrenness and death. – Louis Pasteur

Since the most ancient times, all men, and particularly those who endeavored in the practice of medicine, have brought closer together two natural phenomena of capital importance: illness or fever and fermentation. – Louis Pasteur

Science and peace will triumph over ignorance and war. – Louis Pasteur

My opinion – nay more, my conviction- is that, in the present state of science, as you rightly say, spontaneous generation is a chimera ; and it would be impossible for you to contradict me, for my experiments all stand forth to prove that spontaneous generation is a chimera. – Louis Pasteur

I am on the edge of mysteries and the veil is getting thinner and thinner. – Louis Pasteur

In the fields of observation chance favors only those minds which are prepared. – Louis Pasteur

After death, life reappears in a different form and with different laws. It is inscribed in the laws of the permanence of life on the surface of the earth and everything that has been a plant and an animal will be destroyed and transformed into a gaseous, volatile and mineral substance. – Louis Pasteur

Without theory, practice is but routine born of habit. Theory alone can bring forth and develop the spirit of invention. … [Do not] share the opinion of those narrow minds who disdain everything in science which has not an immediate application. … A theoretical discovery has but the merit of its existence: it awakens hope, and that is all. But let it be cultivated, let it grow, and you will see what it will become. – Louis Pasteur

In good philosophy, the word cause ought to be reserved to the single Divine impulse that has formed the universe. – Louis Pasteur

Nothing is lost and nothing is created in the operations of art as those of nature. – Louis Pasteur

In that memorable year, 1822: Oersted, a Danish physicist, held in his hands a piece of copper wire, joined by its extremities to the two poles of a Volta pile. On his table was a magnetized needle on its pivot, and he suddenly saw (by chance you will say, but chance only favors the mind which is prepared) the needle move and take up a position quite different from the one assigned to it by terrestrial magnetism. A wire carrying an electric current deviates a magnetized needle from its position. That, gentlemen, was the birth of the modern telegraph. – Louis Pasteur

Every chemical substance, whether natural or artificial, falls into one of two major categories, according to the spatial characteristic of its form. The distinction is between those substances that have a plane of symmetry and those that do not. The former belong to the mineral, the latter to the living world. – Louis Pasteur

Herrmann Pidoux and Armand Trousseau stated ‘Disease exists within us, because of us, and through us’, Pasteur did not entirely disagree, ‘This is true for certain diseases’, he wrote cautiously, only to add immediately: ‘I do not think that it is true for all of them’. – Louis Pasteur

These are the living springs of great thoughts and great actions. Everything grows clear in the reflections from the Infinite. – Louis Pasteur

Great problems are now being handled, keeping every thinking man in suspense; the unity or multiplicity of human races; the creation of man 1,000 years or 1,000 centuries ago; the fixity of species, or the slow and progressive transformation of one species into another; the eternity of matter; the idea of a God unnecessary: such are some of the questions that humanity discusses nowadays. – Louis Pasteur

Science knows no country because it is the light that iluminates the world – Louis Pasteur

I give them experiments and they respond with speeches. – Louis Pasteur

Happy is he who bears a god within. – Louis Pasteur

Did you ever observe to whom the accidents happen? Chance favors only the prepared mind. – Louis Pasteur

Could I but know all, I would have the faith of a Breton peasant woman – Louis Pasteur

When one works and imagines and dreams of nothing else than the search for answers that God has posed, it is difficult to be so still. – Louis Pasteur

The nights seem to me too long… I am often scolded by Madame Pasteur, but I tell her I shall lead her to fame. – Louis Pasteur