Will and intellect are one and the same thing.

All things excellent are as difficult as they are rare.

He alone is free who lives with free consent under the entire guidance of reason.

Men would never be superstitious, if they could govern all their circumstances by set rules, or if they were always favoured by fortune: but being frequently driven into straits where rules are useless, and being often kept fluctuating pitiably between hope and fear by the uncertainty of fortune's greedily coveted favours, they are consequently for the most part, very prone to credulity.

The virtue of a free man appears equally great in refusing to face difficulties as in overcoming them.

Yet nature cannot be contravened, but preserves a fixed and immutable order.

The safest way for a state is to lay down the rule that religion is comprised solely in the exercise of charity and justice, and that the rights of rulers in sacred, no less than in secular matters, should merely have to do with actions, but that every man should think what he likes and say what he thinks.