A man must cling to the belief that the incomprehensible is comprehensible; otherwise he would not try to fathom it.  A man does not need to have seen or experienced everything himself.  But if he is to commit himself to another’s experiences and his way of putting them, let him consider that he has to do with three things—­the object in question and two subjects.

If we look at the problems raised by Aristotle, we are astonished at his gift of observation.  What wonderful eyes the Greeks had for many things!  Only they committed the mistake of being overhasty, of passing straightway from the phenomenon to the explanation of it, and thereby produced certain theories that are quite inadequate.  But this is the mistake of all times, and still made in our own day.

Hypotheses are cradle-songs by which the teacher lulls his scholars to sleep.  The thoughtful and honest observer is always learning more and more of his limitations; he sees that the further knowledge spreads, the more numerous are the problems that make their appearance.

If many a man did not feel obliged to repeat what is untrue, because he has said it once, the world would have been quite different.

There is nothing more odious than the majority; it consists of a few powerful men to lead the way; of accommodating rascals and submissive weaklings; and of a mass of men who trot after them, without in the least knowing their own mind.

When I observe the luminous progress and expansion of natural science in modern times, I seem to myself like a traveler going eastward at dawn, and gazing at the growing light with joy, but also with impatience; looking forward with longing to the advent of the full and final light, but, nevertheless, having to turn away his eyes when the sun appeared, unable to bear the splendor he had awaited with so much desire.

We praise the eighteenth century for concerning itself chiefly with analysis.  The task remaining to the nineteenth is to discover the false syntheses which prevail, and to analyze their contents anew.

A school may be regarded as a single individual who talks to himself for a hundred years, and takes an extraordinary pleasure in his own being, however foolish and silly it may be.

In science it is a service of the highest merit to seek out those fragmentary truths attained by the ancients, and to develop them further.

Nature fills all space with her limitless productivity.  If we observe merely our own earth, everything that we call evil and unfortunate is so because Nature cannot provide room for everything that comes into existence, and still less endow it with permanence.

The finest achievement for a man of thought is to have fathomed what may be fathomed, and quietly to revere the unfathomable.

There are two things of which a man cannot be careful enough:  of obstinacy, if he confines himself to his own line of thought; of incompetency, if he goes beyond it.