1/14/2015

Value theory: What is the good life? What's worth pursuing for its own sake?

Normative ethics: What're our fundamental moral duties? What counts as virtues, vices and why?

Metaethics: What's the status of moral claims and advice?

Certainly, many laws require what morality requires, and forbid what morality forbids. But the fit is hardly perfect, and that shows that morality is something different from the law. Good manners, similarly, are not the same thing as morally good conduct. The same is true when it comes to self-interest or tradition. In terms of tradition, people sometimes speak of conventional morality, which is the set of traditional principles that are widely shared within a culture or society. However, some social standards and mutual endorsement can be morally mistaken. As a result, the moral we refer to in this context are standards that are independent of conventional morality and ca be used to critically evaluate its merits. This implies the existence of some independent, critical morality that
(1) doesn't have its origin in social agreements
(2) is untainted by mistaken beliefs, irrationality, or popular prejudices
(3) can serve as the true standard for determining when conventional morality has got it right and when it has fallen into error.

How to distinguish between valid and invalid arguments.
(1) identify all of an argument's premises
(2) imagine that all of them are true
(3) ask yourself: suppose all premises were true, could the conclusion be false? If yes, the argument is invalid. If no, the statement is valid.

But a valid argument is not enough, because in testing the logical structure we assumed the truth of premises, which might not be the case. What we need is a sound argument, and that means the logic is valid and premises are true.

Example:
premise: it is morally acceptable for nonhuman animals to kill and eat other animals
conclusion: it is morally acceptable for human beings to kill and eat other nonhuman animals.

the premise doesn't logically support the conclusion. (What is morally acceptable for animals is not necessarily morally acceptable for us)

This shows that this particular way of defending is no good.

A valid argument:
premises:
(1)if it is morally acceptable for nonhuman animals to kill and eat another, then it is morally acceptable for humans to kill and eat other nonhuman animals.
(2)it is morally acceptable for nonhuman animals to kill and eat other animals
conclusion:
it is morally acceptable for human beings to kill and eat other nonhuman animals

The argument is valid but the first premise is wrong. Animals are not moral agents--they cannot control their behavior through moral reasoning, and thus it is not convincing to look to animals for moral guidance.