Fallen human beings are really good at rationalizing. All of us are. We find ingenious ways of telling ourselves that things we want to do are really okay, even when they’re not.

One of our favorite tools is appealing to the fact that we have a good end in view. This kind of rationalization is often used to justify abortion and contraception. Couples will say that these are justified because it “isn’t the right time” to have a baby.

And they may be right about that. There are many reasons why a given couple shouldn’t have a baby — e.g., they’re not married; it would jeopardize the mother’s life or health; it would involve severe hardship.

All of those are good reasons not to have a baby, so the couple may indeed have a good end in mind. In this case, the question wouldn’t be whether the end is good, but whether the means being used to achieve it are good.

Many people today think that the means would be good. “The ends justify the means” is a common sentiment.

Some moral philosophers and theologians have even built ethical theories around this idea. Since they focus on the ends toward which actions are directed, they are called “teleological” theories, from the Greek word telos, which means “end.”

They’re also called “consequentialist” theories, because they make the consequences of an action the ultimate key to deciding whether it is good or bad.

Consequentialist theories are appealing to many people. One of the most popular is utilitarianism, which holds that we should always act in the way that brings about the greatest good for the greatest number of people.

This good might be understood in terms of happiness, pleasure or something else, but the idea is that promoting the common good is the ultimate test of moral behavior.

The reason so many people find this an attractive proposition is that the consequentialists have a genuine insight here: The consequences of our actions do matter, and we do need to promote the common good.

Consequentialists have tapped into genuine moral insights, and that gives their theory a measure of plausibility.

But let’s think this through. What would it mean if we judged our actions solely by the consequences they have?

One thing it would mean is that we couldn’t ever really be sure if what we were doing was right or wrong because we don’t have a reliable way of measuring the consequences of our actions. There’s no “goodness scale” on which we can objectively evaluate them. We can only use our gut impressions.

Further, our gut impressions are often wrong. We’ve all had the experience of trying to help someone, only to realize that we’ve made the situation worse. Unintended consequences are very real, and they happen all the time.

Our actions also have consequences that extend far into the future.

For example, the decision to have — or not have — a baby has the potential to affect all future generations. Consider: The childbearing decisions of each one of your ancestors, all the way back to the beginning, are still having consequences all this time later (your life being one of them).

But our minds aren’t designed to peer that far into the future and take account of all the consequences — good and bad — that our actions in the here and now will have down the line. We simply aren’t built for that.

When you think about what consequentialism entails, a new ethical intuition emerges, which is that we simply can’t be responsible for calculating the consequences of our actions in a rigorous way, and so there must be something more to ethical behavior than figuring out their ultimate consequences.

However, there is an even more fundamental problem with consequentialism: It would literally justify anything.

Putting on show trials and executing people you know to be innocent? Raping women? Sexually molesting children?

All of these could be justified in some circumstances, because according to consequentialism, the action itself doesn’t matter; it’s only the consequences that do. If, in a particular circumstance, you deemed the consequences to be a net plus, you’d be justified in doing it.

And lest you think that nobody ever tries to justify such actions, they do. Show trials are just one example. Totalitarian regimes have often executed people known to be innocent on the grounds that it will help society hang together and obey the laws. Every rapist thinks the pleasure he’s going to get outweighs the harm he’s doing. Pedophiles sometimes even claim they’re “helping” children!

But we don’t need to do a harm-benefit calculus to recognize that these actions are just wrong. If our ethical intuitions are functioning properly, they shout the fact that these things are simply not to be done, that they are evil in and of themselves.

Consequentialism thus runs up against another set of ethical intuitions, which reveal that consequences aren’t the only things we should be taking into account when we make ethical decisions.

So what should we consider? The Church teaches that the morality of an action depends on three things:

(1) the nature of the act we’re choosing to do,

(2) the end we are pursuing by it, and

(3) the circumstances in which we do it (see Catechism of the Catholic Church, 1750-1761).

All three must be good in order for the action to be good. This is why considering the consequences alone is not enough. They pertain to the end we are pursuing — the ultimate consequence we want to bring about. They also pertain to the circumstances, which may involve unintended consequences. But the action itself must be a good one.

Killing innocent people, raping women and molesting children — all of these are wrong by their very nature. There is something broken in a person when he uses the faculties God has given him to do any of these things.

Such actions are said to be “intrinsically disordered” because their very nature involves a misuse of God’s gifts. They are also said to be “intrinsically evil” because they are wrong by their very nature.

And so the means do not justify the ends (Romans 3:8). That’s why abortion and contraception aren’t justified even if it “isn’t the right time” to have a baby.

God designed the sexual act to be used in marriage, and spouses can’t deliberately break what God designed. If they need to avoid having a baby, they need to work in harmony with God’s plan, not thwart it.

Further, whether married or not, once a mother is pregnant, she has a baby, and that baby is an innocent human being who cannot be killed.

Consequentialist theories of ethics may be appealing because they incorporate the ethical intuition that the consequences of our actions are important, but they ignore other fundamental ethical intuitions, such as the fact that we aren’t built to foresee all the consequences of our actions and that some actions are intrinsically disordered and evil.

In other words, some things are just plain wrong.

Jimmy Akin is the senior apologist at Catholic Answers,

a contributing editor to Catholic Answers Magazine

and a weekly guest on Catholic Answers Live. He blogs at NCRegister.com.