Critique of Practical Reason

Kant notes that there are two things that “fill the mind with ever new and increasing admiration and reverence…the starry heavens above me and the moral law within me” (129). The first is a reminder of his mortality and insignificance as a physical being, while the second reveals his significance as an intelligence. Both reveal that Kant has a consciousness through which he can work to understand the infinite reality and “countless multitude of worlds” (129) before him.

However, even this admiration for the external universe and the internal moral law can only be a starting point toward reason. In fact, it can lead people astray: Observation of the skies encouraged the false science of astrology, while the study of morals brought about “enthusiasm” and “superstition” (130). Only reason can overcome such dead ends, Kant writes. He holds out the hope that moral reason can be studied scientifically like mathematics or chemistry. A science of morality, supported by philosophy, could one day be established and prevent false ideas from developing.