Two things fill the mind with ever new and increasing admiration and reverence, the more often and more steadily one reflects on them: the starry heavens above me and the moral law within me.
Kant compares the physical and the moral sciences. Both start from self-evidence sources of wonder. Although both are right before us, though, a true understanding of either is not easy to find. Both have been lost for a long time in superstition and blind conjecture. The physical sciences have finally reached a point where they are developing rationally. The moral sciences have not reached that point yet, but Kant hopes to pioneer a scientific, rational approach to ethics in his work. The method Kant uses in the Analytic, which imitates that of a geometrical treatise, both reflects this optimism and is meant to further this rationalizing of ethics. By carefully separating off the a priori foundations of ethics from anything empirical, and then proceeding through a series of proofs to the most fundamental moral principle, Kant hopes to improve on the method of doing ethics. Later, the application of this principle can be spelled out by looking at the empirical world. To look at the empirical world while pulling out the fundamental principle, though, he regards as fatal to clarity and rigor.