He who is of a calm and happy nature, will hardly feel the pressure of age

Every serious man in dealing with really serious subjects carefully avoids writing. ... There does not exist, nor will there ever exist, any writing of mine dealing with this subject.

Let no one destitute of geometry enter my doors.

Those who intend on becoming great should love neither themselves or their own things, but only what is just, whether it happens to be done by themselves or others.

To the rulers of the state then, if to any, it belongs of right to use falsehood, to deceive either enemies or their own citizens, for the good of the state: and no one else may meddle with this privilege.

In the world of knowledge, the essential Form of Good is the limit of our inquiries, and can barely be perceived; but, when perceived, we cannot help concluding that it is in every case the source of all that is bright and beautiful -in the visible world giving birth to light and its master, and in the intellectual world dispensing, immediately and with full authority, truth and reason -and that whosoever would act wisely, either in private or in public, must set this Form of Good before his eyes.

Sin is disease, deformity, and weakness.