I closed the previous lecture with this statement:

“This shared human experience is what makes moral argumentation possible.”

How does our shared moral experience make moral argumentation possible?

It makes it possible because, in virtue of this shared moral experience, I can assert moral claims that most people are willing to accept as true.

These claims can then function as premises in a moral argument, even if we are completely divided philosophically on what makes a moral claim true or false.

Let me give you an example.

Raise your hand if you think it’s wrong to kill another person for pleasure.

All hands up? Good.

Because of this agreement, I can write an argument like this …

1. It’s morally wrong to kill another person for pleasure.
2. Tommy killed his cousin Rick for pleasure.
Therefore, what Tommy did was morally wrong.

… and this argument will make perfect sense to you. You can see at a glance that the conclusion follows from the premises, and the key moral premise strikes you as obviously true. You can easily read and evaluate this as an argument.

But now let me ask you — why is it morally wrong to kill another person for pleasure?

Another way to phrase the question: if it’s wrong, what makes it wrong?

Are you confident in your answer?

You might be surprised at the diversity of replies you’ll get if you ask this question. Try it over dinner some time.

Here are some replies you might hear:

“It’s wrong because he’s taking pleasure in it, and that’s just evil.”

“It’s wrong because it violates one of God’s commandments — thou shalt not kill.”

“It’s wrong because it violates another person’s right to life.”

“It’s wrong because any sane culture would say it’s wrong. If we allowed murder like this to go on without punishment we wouldn’t have any social order.”

These are very different answers. There’s far less agreement on the question of why killing for pleasure is wrong, than the initial judgment that killing for pleasure is wrong.

This is hardly surprising. The question “what makes an act morally right or wrong?” is a question for moral philosophy. Within the Western philosophical tradition there is 2500 years of debate on what grounds the truth of moral claims.

Fortunately, what matters in this example, from the standpoint of moral argumentation, isn’t why we think it’s wrong to kill a person for pleasure, only that we think it’s wrong.

If the premises you’re offering are ones that your intended audience is willing to accept as true, for whatever reason, then they can serve as reasons for your audience to accept what logically follows from those premises.

In the case of moral argumentation, all we need are moral premises that an audience is willing to accept as true. The stronger and wider the agreement on the premises, the more effective the argument can be.

Obviously, people disagree about many moral issues (abortion, capital punishment, welfare, war, pornography, homosexuality, …).

These are the precisely the issues about which people feel compelled to formulate moral arguments.

But we can only argue about these issues if there ALSO exists a large collection of moral judgments about which the arguer, and the intended audience of the argument, agree. These are the claims that we can rely on as plausible moral premises, or shared background assumptions, in moral arguments.

Fortunately, among groups there is often a great deal of common moral ground that can serve as a foundation for constructive moral argument and debate.

Most of us agree, for example, that happiness is a good thing and suffering is a bad thing, all other things being equal.

Most of us agree that restricting the freedom of other people, for no good reason, is a bad thing (again, all other things being equal).

Most of us agree that courage and compassion are moral virtues, not vices.

We could go on.

Of course there is variation in shared moral values across cultures, age groups, religious groups, historical periods, etc. Think of differing moral attitudes between religious conservative and secular liberals, or between younger people and older people.

These differences in moral values can pose a challenge to productive moral dialogue and debate between these different groups.

One of the goals of this course is to provide some tools that can help meet this challenge.