“How do you know that in ten thousand years, one will not consider it more likely that matter has emerged from life?”

Partially quoted in René Dubos, Louis Pasteur: Free Lance of Science, Da Capo Press, Inc., 1950. p 396.
Original in French: «La génération spontanée, je la cherche sans la découvrir depuis vingt ans. Non, je ne la juge pas impossible. Mais quoi donc vous autorise à vouloir qu'elle ait été l'origine de la vie? Vous placez la matière avant la vie et vous faites la matière existante de toute éternité. Qui vous dit que, le progrès incessant de la science n'obligera pas les savants, qui vivront dans un siècle, dans mille ans, dans dix mille ans... à affirmer que la vie a été de toute éternité et non la matière.? Vous passez de la matière à la vie parce que votre intelligence actuelle, si bornée par rapport à ce que sera l'intelligence des naturalistes futurs, vous dit qu'elle ne peut comprendre autrement les choses. Qui m'assure que dans dix mille ans on ne considérera pas que c'est de la vie qu'on croira impossible de ne pas passer à la matière? Si vous voulez être au nombre des esprits scientifiques, s, qui seuls comptent, il faut vous débarrasser des idées et des raisonnements a priori et vous en tenir aux déductions nécessaires des faits établis et ne pas accorder plus de confiance qu'il ne faut aux déductions de pures hypothèses." (Pasteur et la philosophie,Patrice Pinet, Editions L'Harmattan, p. 63.
Context: I have been looking for spontaneous generation for twenty years without discovering it. No, I do not judge it impossible. But what allows you to make it the origin of life? You place matter before life and you decide that matter has existed for all eternity. 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? You pass from matter to life because your intelligence of today cannot conceive things otherwise. How do you know that in ten thousand years, one will not consider it more likely that matter has emerged from life? You move from matter to life because your current intelligence, so limited compared to what will be the future intelligence of the naturalist, tells you that things cannot be understood otherwise. If you want to be among the scientific minds, what only counts is that you will have to get rid of a priori reasoning and ideas, and you will have to do necessary deductions not giving more confidence than we should to deductions from wild speculation.

Go Rin No Sho (1645), The Ground Book
Context: These things cannot be explained in detail. From one thing, know ten thousand things. When you attain the Way of strategy there will not be one thing you cannot see. You must study hard.

Source: Jonathan Livingston Seagull

From the lyrics of his song Vida Louca, Vida (Life, Crazy Life)

Down and Out in the Magic Kingdom (2003)

Man and Socialism in Cuba (1965)

Elmer Gantry (1927)

Source: Meditations (c. AD 121–180), Book VII, 49

"Father Severyan", in November 1916: The Red Wheel: Knot II (1984; translation 1999).
Context: At no time has the world been without war. Not in seven or ten or twenty thousand years. Neither the wisest of leaders, nor the noblest of kings, nor yet the Church — none of them has been able to stop it. And don't succumb to the facile belief that wars will be stopped by hotheaded socialists. Or that rational and just wars can be sorted out from the rest. There will always be thousands of thousands to whom even such a war will be senseless and unjustified. Quite simply, no state can live without war, that is one of the state's essential functions. … War is the price we pay for living in a state. Before you can abolish war you will have to abolish all states. But that is unthinkable until the propensity to violence and evil is rooted out of human beings. The state was created to protect us from evil. In ordinary life thousands of bad impulses, from a thousand foci of evil, move chaotically, randomly, against the vulnerable. The state is called upon to check these impulses — but it generates others of its own, still more powerful, and this time one-directional. At times it throws them all in a single direction — and that is war.