Those who hope for no other life are dead even for this.

My counsel is, to force nothing, and rather to trifle and sleep away all unproductive days and hours, than on such days to compose something that will afterwards give no pleasure.

On the pinnacle of success man does not stand firm long.

We must not take the faults of our youth with us into old age, for age brings along its own defects.

Mathematics has the completely false reputation of yielding infallible conclusions. Its infallibility is nothing but identity. Two times two is not four, but it is just two times two, and that is what we call four for short. But four is nothing new at all. And thus it goes on and on in its conclusions, except that in the higher formulas the identity fades out of sight.

I hate all explanations; they who make them deceive either themselves or the other party,-generally both.

No two men see the world exactly alike, and different temperaments will apply in different ways a principle that they both acknowledge. The same man will, indeed, often see and judge the same things differently on different occasions: early convictions must give way to more mature ones. Nevertheless, may not the opinions that a man holds and expresses withstand all trials, if he only remains true to himself and others?