“Immanuel Kant (1724-1804) follows Rousseau in his moral philosophy. Earlier in his career, Hume’s thought had made him realize that objective knowledge of nature as it appears to the senses (i.e. laws of natural phenomena) required not on a priori concepts or categories, but also a posteriori sense intuitions: “Concepts without sense intuitions are empty; sense intuitions without concepts are blind.” The causal laws governing natural phenomena are absolutely universal and necessary, so nature is deterministic. Beyond the sphere of nature that can be objectively known is the rational or the noumenal sphere of liberty. Here, according to Kant, we cannot attain objective knowledge, but only rational beliefs or postulates concerning such things as the freedom and immortality of the human soul, the world as a whole, and God—they cannot be known objectively since we cannot perceive them with our senses), but only thought about rationally. In the Groundwork for a Metaphysics of Morals, Kant spells out the basis for morality in the freedom of the good will from the determinist causality of physical natural phenomena. “Nothing in the world, indeed nothing even outside the world can be considered good without limitation except a good will.” Humans have this good will prior to becoming virtuous, because it is reason as concerned with action. By it we are able to cause ourselves, even though this good will cannot be intuited in space and time and is not subject to ordinary causal necessity. As such good will is autonomous (= self-legislating vs. following the law of another = heteronomy). It is the capacity to do one’s duty instead of seeking happiness (Kant opposes eudaemonistic [happiness-oriented] ethics because he thinks of them as enslaving man to pleasure), or following lower desires or fears, or obeying outside social customs, etc. Instead it is the capacity to apply and follow the categorical (which means absolutely necessary and universal as opposed to hypothetical or conditional) imperative. The categorical imperative is the universalization of a rule or maxim one gives oneself: Act in such a way that the command you give yourself would be a universal law for anyone else, too. Don’t make any exceptions for yourself. Kant also formulates this categorical imperative in terms of the so-called “kingdom of ends:” Never use another person as a means for any purpose they have not freely chosen themselves; always treat others as ends rather than as means” (Frederick Lawrence, Philosophers and Theologians, Boston College).