Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me. I do not seek or conjecture either of them as if they were veiled obscurities or extravagances beyond the horizon of my vision; I see them before me and connect them immediately with the consciousness of my existence.

In every department of physical science there is only so much science, properly so-called, as there is mathematics.

...[R]eason of itself, independent on all experience, ordains what ought to take place, that accordingly actions of which perhaps the world has hitherto never given an example, the feasibility even if which might be very much doubted by one who founds everything on experience, are nevertheless inflexibly commanded by reason; that, for example, even though there might never yet have been a sincere friend, yet not a whit the less is pure sincerity in friendship required of every man...

...[P]hysics... [is] the philosophy of nature, so far as it is based on empirical laws.

The infinitude of creation is great enough to make a world, or a Milky Way of worlds, look in comparison with it what a flower or an insect does in comparison with the Earth.

If it were possible for us to have so deep an insight into a man's character as shown both in inner and in outer actions, that every, even the least, incentive to these actions and all external occasions which affect them were so known to us that his future conduct could be predicted with as great a certainty as the occurrence of a solar or lunar eclipse, we could nevertheless still assert that the man is free.

Our intellect does not draw its laws from nature, but it imposes its laws upon nature.

An organized product of nature is that in which all the parts are mutually ends and means.

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.