“Each problem that I solved became a rule which served afterwards to solve other problems.”

There is nothing more ancient than the truth.

When it is not in our power to determine what it true, we ought to follow what is most probable.

For I found myself embarrassed with so many doubts and errors that it seemed to me that the effort to instruct myself had no effect other than the increasing discovery of my own ignorance

All that is necessary to right action is right judgment, and to the best action the most correct judgment.

I desire to live in peace and to continue the life I have begun under the motto ‘to live well you must live unseen’.

Truths are more likely to have been discovered by one man than by nation

I doubt, therefore I think, therefore I am.

But what then am I? A thing that thinks. What is that? A thing that doubts, understand, affirms, denies, wills, refuses, and that also imagines and senses.

He who hid well, lived well.

Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.

One should never judge anything unless it is known

That we conduct our thoughts along different ways, and do not fix our attention on the same objects.

It is a common failing of mortals to deem the more difficult the fairer.

The reading of all good books is like conversation with the finest men of past centuries.

The will determines itself; it should not be described as blind, any more than vision should be described as deaf.

But in my opinion, all things in nature occur mathematically.

And it was always without pretensions of loving or being loved although always in the hope of finding something that resembled love but without the problems of love.

I, personally, have a lot of energy, so I don’t see it as an immediate problem.

Separation of powers is a problem for foreign policy.

A lot of people have problems with public confrontation, but it doesn’t worry me at all. I can handle myself. I know my martial arts.

Problems are just mile markers. Each one we pass means we’ve gotten better.

Face your problems! Unless your problem is your face.

We’ve really got to stop looking to Washington to fix our problems. It obviously doesn’t have the ability to do that. People who are successful are not successful because of the president.

Let the puzzle solve itself.