Wonder is the first of all passion.

At last I will devote myself sincerely and without reservation to the general demolition of my opinions.

For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it.

Intuitive knowledge is an illumination of the soul, whereby it beholds in the light of God those things which it pleases Him to reveal to us by a direct impression of divine clearness.

Now therefore, that my mind is free from all cares, and that I have obtained for myself assured leisure in peaceful solitude, I shall apply myself seriously and freely to the general destruction of all my former opinions.

There is nothing so far removed from us to be beyond our reach, or so far hidden that we cannot discover it.

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

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

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

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

The first precept was never to accept a thing as true until I knew it as such without a single doubt.

Any community that gets its laughs by pretending to be idiots will eventually be flooded by actual idiots who mistakenly believe that they're in good company.

Because reason...is the only thing that makes us men, and distinguishes us from the beasts, I would prefer to believe that it exists, in its entirety, in each of us.

I was convinced that our beliefs are based much more on custom and example than on any certain knowledge.

And as it is the most generous souls who have most gratitude, it is those who have most pride, and who are most base and infirm, who most allow themselves to be carried away by anger and hatred.

Although my knowledge grows more and more, nevertheless I do not for that reason believe that it can ever be actually infinite, since it can never reach a point so high that it will be unable to attain any greater increase.

It is contrary to reasoning to say that there is a vacuum or space in which there is absolutely nothing.

Reason is the only thing that makes us men, and distinguishes us from the beasts.

Whenever anyone has offended me, I try to raise my soul so high that the offense cannot reach it.

The senses deceive from time to time, and it is prudent never to trust wholly those who have deceived us even once.