How do you explain that murder is wrong to an atheist who seems to believe the contrary? And what is the difference between murder and killing, is it ever justifiable? How do you explain death by self defense or in war?
Start by asking if it would be OK for you to kill him/her because you disagree on religion/philosophy.
If the answer is yes, then stop. Either the moral gap between you is too large, or they are being intentionally argumentive - that is, no legitimate interest in your point of view.
If the answer is no, then point out, you agree. You both are ‘pro-life’, the only disagreement is on degree.
There are several good ways of discussing our understanding on right to life. First, you could look at the Good Samaritan, it is one of the parables in the Bible with which most people are at least vaguely familiar. Start by explaining the context, Jesus is asked a question about salvation (the questioner had motives, but we can leave that out). The simple answer was, Love God with all your heart and love your neighbor as yourself.
Then comes the question about who is my neighbor. Jesus gives an example of a man in distress. But it is important to understand the central characters in the context of Jesus’ original listeners. Tell the ‘aethiest’ to imagine being a Jewish holocaust survivor. Then imagine being severely beaten, robbed, and left for dead.
A beloved and respected Rabbi then comes by, but does nothing. Not necessarily because he has no sympathy, but because he is caught up in strict interpretation of the complicated laws in the Jewish Bible (see purity laws on contact with the dead).
Next comes a respected and loved Church elder, who also passes by. Perhaps because of the laws, perhaps because of weakness.
Finally comes a Nazi, who stops and helps…
One of the morals to the story is that all of mankind is our ‘neighbor’. So we are supposed to love everyone, not just in a vague way, but with the intensity with which we love and respect ourselves.
Further, we Catholics believe that each of us possesses a soul which is a unique creation of God, who also loves each of us infinitely.
Now combine these two, we should value other people’s hides as much as we value our own. And, if we love God with all our hearts, we should treasure and respect the other creations he loves.
Many in the secular community think that “right to life” means conception to birth. And that might be true in some Evangelical circles. But in Catholicism, we define the right to life applying to all stages and all states. In other words, we strive to love all of humankind as ourselves and give the utmost respect to each unique creation of a loving God. Look at these instructions that Pope John Paul II wrote to the lay members of the Church on this teaching:
"In effect the acknowledgment of the personal dignity of every human being demands the respect, the defence and the promotion of the rights of the human person. It is a question of inherent, universal and inviolable rights. No one, no individual, no group, no authority, no State, can change-let alone eliminate-them because such rights find their source in God himself.
The inviolability of the person which is a reflection of the absolute inviolability of God, fínds its primary and fundamental expression in the inviolability of human life. Above all, the common outcry, which is justly made on behalf of human rights-for example, the right to health, to home, to work, to family, to culture- is false and illusory if the right to life, the most basic and fundamental right and the condition for all other personal rights, is not defended with maximum determination.
The Church has never yielded in the face of all the violations that the right to life of every human being has received, and continues to receive, both from individuals and from those in authority. The human being is entitled to such rights,
in every phase of development, from conception until natural death; and in
every condition, whether healthy or sick, whole or handicapped, rich or poor. The Second Vatican Council openly proclaimed: <<All offences against life itself, such as every kind of murder, genocide, abortion, euthanasia and willful suicide; all violations of the integrity of the human person, such as mutilation, physical and mental torture, undue psychological pressures; all offences against human dignity, such as subhuman living conditions, arbitrary imprisonment, deportation, slavery, prostitution, the selling of women and children, degrading working conditions where men are treated as mere tools for profit rather than free and responsible persons; all these and the like are certainly criminal: they poison human society; and they do more harm to those who practice them than those who suffer from the injury. Moreover, they are a supreme dishonour to the Creator>>" - CHRISTIFIDELES LAICI, #38
When you read a reasonably decent person, secular or not, the above list, they will usually find a lot they agree with. You can build on that.
