Two things fill the mind with ever-increasing wonder and awe, the more often and the more intensely the mind of thought is drawn to them: the starry heavens above me and the moral law within me.

Kant’s famous line comes from the conclusion of his Critique of Practical Reason (1788), where he sums up the distinctive “facts” that most powerfully move human reason. Writing in late Enlightenment Prussia, Kant had argued that theoretical reason is limited in what it can know about ultimate reality, but practical reason discloses an unconditional moral obligation—the moral law—experienced as duty. In the closing pages he juxtaposes two objects of contemplation: the vast, law-governed cosmos revealed by astronomy (“the starry heavens”) and the inner awareness of moral obligation (“the moral law within”). The pairing dramatizes his project of grounding ethics in reason while acknowledging humanity’s place in nature.

The sentence contrasts two sources of awe that deepen with reflection: the external order of nature and the internal authority of conscience. The “starry heavens” evoke the immensity and regularity of the physical universe, which can make the individual feel small and contingent. The “moral law within,” by contrast, points to a different kind of greatness: the capacity of rational agents to recognize and bind themselves to universal duty. Together they express Kant’s dual vision of the human being as both a natural creature subject to causal laws and a moral person capable of autonomy. The quote’s significance lies in how it frames ethics not as sentiment or custom, but as a rational law that commands reverence comparable to that inspired by the cosmos.

1) “Two things fill the mind with ever new and increasing admiration and awe…: the starry heavens above me and the moral law within me.”
2) “Two things inspire me to awe… the starry sky above and the moral law within.”
3) “The starry heavens above me and the moral law within me.”