The logic behind the Catholic Church being anti-abortion is very straightforward. We have two options in life:

1. We can be selfish and narcissistic, or
2. We can be altruistic.

The third option of being “sometimes selfish and sometimes altruistic” is not a real option. In reality, this person is merely practicing “enlightened self-interest” — that is, being selfish when it behooves him and otherwise appearing to be altruistic at other times. This is distinct from being a normal, sinful person who, though he tries to be good, will sometimes fail. This individual at least understands that altruism — that is, the love of others — is the only real, moral, objective and authentic way of living.

If we live only for ourselves and consider this a sane, rational and intelligent option in keeping with our free choice, then we can’t be upset and complain when others act similarly. That is, if one person can claim the right to be selfish, how can that individual then claim it’s wrong for others to act this way toward him? Their actions aren’t universalizable and therefore irrational and immoral. To continue acting in this manner would be irrational.

If we chose to live for others―whether the other is a neighbor in need or a child in the womb―we will never encounter the problem of what happens when people emulate us. In fact, altruistic people would naturally hope and even presume that everyone should, indeed, be altruistic.

This is the principle difference between good and evil. Good people want and hope others will emulate them. Evil people hope and pray that no one will copy them. If everyone acted as they do, wicked people would be having a very bad time of it — as would the rest of us, incidentally.

Evil is irrational, not universalizable, unsustainable and self-defeating. Good is rational, universalizable, life-sustaining and peaceful. Evil inevitably causes conflict and causes the holder of such an outlook to hope against hope that people won't agree with them. An individual who claims he shouldn’t help those in distress can't, when his fortunes change and finds himself in need, then decry those who refuse to help him. That would be selfish, morally inconsistent and irrational. Evil people prefer to deal with good people rather than others of their own ilk—altruists are easier to deal with. Good people prefer to deal with other good people who behave and think like themselves. Good laws, even in a secular society, are based on this obvious, very rational concept.

As can be seen, good and evil aren’t as relative as secularists would have us believe.

Now that we've identified good as the only rational and universalizable way of acting, the question remains how do we come to a decision about abortion. This question is a great deal easier than the first question. If scientific reality teaches us that the embryo is, by virtue of its genetic makeup and the fact that human procreation and gestation proceeds in one way―and in one way only―it follows that no innocent human being should ever be killed. Not “wanting” the child is not a good reason to kill a human being nor is the desire for freedom of expression acceptable. Killing is killing, and killing an innocent human being is never good. Thus, the nature of good demands we eschew abortion.

But, putting aside Christ and his holy Catholic Church for the briefest moment, let’s speak of the question of abortion merely from a scientific perspective. Further, let’s take the nihilism that atheism preaches―that the universe comes with no instruction manual or inherent moral code―and that everything is relative. Now what?

The Principle of Evolution isn’t furthered if we kill our children. Rather, it’s the evolutionary equivalent of suicide. Those who live without children aren’t able to represent their genes in succeeding generations. They are an evolutionary dead end.

Why would “bodily autonomy” mean anything in such amoral, meaningless? Why would it matter if someone was pro-abortion or against it? If everything is truly relative and there’s no way to say one is good while the other is evil, why would anyone be angered when discussing abortion According to the moral relativist, there’s no more inherent goodness or rightness to being pro-abortion than there is to being pro-life.

• Even free will isn’t a consideration if the nihilist/post-modernist insists that it doesn’t exist. And, without free will, being “pro-choice” means absolutely nothing:
• There is no justice in an arbitrary, meaningless and amoral universe, so to beg for it as a last resort is a waste of time.
• If there is no meaning or morality or even logic in the universe, then “human dignity” and “human rights” are fictional constructs. After all, it’s called “nihilism” for a reason.
• Logically, this would mean that rapists to decide if rape is a good idea also. After all, there’s the matter of free will. Without morality, free will is merely a dictate of tastes―one person “feels” this is good for him and another person “feels” this is not good for him. And, as the Romans always admitted, De gustibus non disputandum est. (Latin: “Do not argue about tastes.”) And if the fiction of human choice is pressed, then it follows that if I don’t want to have abortion practiced in my nation, then I get to have my choice imposed on everyone else. After all, that’s what pro-abortionists have been doing for the past 50-years.
• A nihilist is hard pressed to deny the concept of free will and insist on making it the linchpin of his argument. Free will could not have originated in nature eo ipso―that is, on its own. If free will exists and it’s not an illusion, from whence shall the nihilist say it comes if not from God? If God then exists, then an objective morality exists and if an objective morality exists, it is the basis of human dignity and as such all murder is wrong.

Abortion is wrong whether you believe in God or not. Pro-abortionists don’t have a leg to stand on. And as they insist on their “emotions” rather than logic, it’s easy to trip them up. And, as atheist-to-Catholic convert science-fiction writer John C. Wright loves to remind us, “If Vulcans had a church, they’d be Catholics.”