To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.

Every light has its shadow, and every shadow hath a succeeding morning.

Of all things visible, the highest is the heaven of the fixed stars.

For I am not so enamoured of my own opinions that I disregard what others may think of them.

The Universe, wrought for us by a supremely good and orderly Creator.

Nations are not ruined by one act of violence, but gradually and in an almost imperceptible manner by the depreciation of their circulating currency, through its excessive quantity.

Finally we shall place the Sun himself at the center of the Universe.

Those things which I am saying now may be obscure, yet they will be made clearer in their proper place.

The massive bulk of the earth does indeed shrink to insignificance in comparison with the size of the heavens.

Mathematics is written for mathematicians.

I am aware that a philosopher's ideas are not subject to the judgment of ordinary persons, because it is his endeavour to seek the truth in all things, to the extent permitted to human reason by God.

Life is something that happens when you can't get to sleep.

We traveled long and forgot why poetry was invented.

I am as I am, and that's all there is to it, I can hardly take a pair of scissors to myself, and cut out a different person...

Am I a professor? Goodness. I expect I was hopeless, was I?

Now let's get talking: reefer madness. Like some arrogant government can't, By any stretch of the imagination, outlaw a plant.

It is almost always wrong that the time isn't ripe to decide something. That is always said of difficult problems.

I was the lead in two musicals, and I took dance classes.

All governments like the ignorant, because their existence depends on them! If the society becomes wise, governments cannot survive, at least the bad ones cannot!

I used to be sure of things. Me, once i had all the answers. I wish i was a kid again, when i had all the answers

She had rooms in her mind that she would not look into.