This was an overview lecture which explained a little more about the breakdown and organization of the course. Koterski explained that his intention will be to look at natural law theory from both a philosophical and historical perspective. The philosophical approach was dealt with some in the first lecture, and here he explains that the historical approach isn’t just to understand the sequence of events in the history of natural law. It is to understand some of the philosophical questions better, in particular, the issue of relativism. Is morality merely a cultural phenomenon? Koterski holds out the promise that by looking at the history of the various insights of natural law and how it developed might help shed some light on this question.
Koterski then quickly explains the essentials of the four major traditions of ethics. He covers Aristotle’s Virtue Ethics, Kant’s Deontology, Mill’s Utilitarianism, and Religious divine command. He covers these in a very simply and basic way, and briefly discusses how they compare and contrast with natural law ethics. My one criticism here is that explains Kant theory as a systematized theory of the golden rule—and that is not an accurate explanation of the categorical imperative.
The next section of the lecture focuses on how natural law can meet the ideals that were laid out in lecture one: objectivity, universality, and intelligibility. Objectivity, he argues, will come from the basing of ethics on our natures as human beings. By asking what kind of beings we are and what our typically activities are, we can find an objective basis for ethical principles. The universality of natural law will come from a similar source in that if all humans share a common nature, the moral principles will be universal across this common nature. Lastly, intelligibility can be found because, it is claimed, one with an open and reasonable mind should be able to discover and understand human nature.
Next are the objections to natural law (and indeed morality itself): relativism, subjectivism, and skepticism. He doesn’t try to answer these concerns here, promising that these will be answer as he argues for natural law.
Lastly, Koterski discusses moral knowledge and natural kinds. Moral knowledge he will argue, is possible, contra the skeptic. He argues that there are certain claims of moral knowledge that it is just implausible to claim we don’t know or that are reasonable to deny. Using murder as an example, he claims it is undeniable that the killing of innocent life is wrong. The rub, of course, is what one considers to be innocent.
A natural kind is a “group that can be objectivity distinguished from another group on the basis of some property.” To be a difference in kind, the trait or property “is present in some degree in every member of the group and is totally lacking in other instances.” Differences in degree are differences along some dimension that all members of the group share. He uses water and salt as an example. Water and salt are different in kind—they are two different natural kinds. They each have a natural structure that gives rise to certain properties that all members of one group have and the other totally lacks. But liquid water, ice, and water vapor are different in degree—they possess related properties based on an essentially similar structure.
He closes the lecture with the question of whether humans are a natural kind. He thinks we are and will argue that the property that makes us different, the one we have that no other creature has, is rationality in the form of intellect and will. He doesn’t think that the possibility that we might find non-human rational creatures shows there is no natural kind—he just thinks he will expand the group of rational creatures are that deserving of respect.