Without man and his potential for moral progress, the whole of reality would be a mere wilderness, a thing in vain, and have no final purpose.

Enlightenment is man's leaving his self-caused immaturity. Immaturity is the incapacity to use one's intelligence without the guidance of another. Such immaturity is self-caused if it is not caused by lack of intelligence, but by lack of determination and courage to use one's intelligence without being guided by another. Sapere Aude! Have the courage to use your own intelligence! is therefore the motto of the enlightenment.

Two things fill the mind with ever new and increasing admiration and awe, the oftener and more steadily we reflect on them: the starry heavens above and the moral law within.

I shall never forget my mother, for it was she who planted and nurtured the first seeds of good within me. She opened my heart to the lasting impressions of nature; she awakened my understanding and extended my horizon and her percepts exerted an everlasting influence upon the course of my life.

I assert that, in any particular natural science, one encounters genuine scientific substance only to the extent that mathematics is present.

Nature even in chaos cannot proceed otherwise than regularly and according to order.

Have patience awhile; slanders are not long-lived. Truth is the child of time; erelong she shall appear to vindicate thee.