I developed my thoughts on violence in dialogue with political thinker Hannah Arendt along with theologians Paul Tillich and Reinhold Niebuhr, sociologist Max Weber, and more recently evolutionary biologists and psychologists like Paul Bloom, Aaron Goetz, DM Buss. Violence, the use of physical force, including the taking of animal and human life, is consistent with human nature as we have evolved. But also consistent with human nature is non-violence in avoiding and settling conflicts and building a non-coercive space for free interaction with living beings, humans, and the world.
Violence belongs to the realm of necessity. Non-violence to the space of freedom. We use violence to satisfy life's needs including production, consumption, reproduction, and the protection of our genetic future. But in the space of freedom where justice is pursued, the coercion of violence is not appropriate except to protect the realm of necessity. Thus violence may be necessary; and indeed it is to serve and protect life. But violence is never an end in itself and can never be justified in civil society. Civilization, the place where persons are citizens, seeks to minimize violence especially in human affairs.
Abortion, like any surgical invasion, is an act of violence and therefore should never be performed except when necessary. Nor indeed should cosmetic surgery, capital punishment, suicide, torture, the killing in war unless it is judged as necessary. But who makes the judgment of necessity? In the case of surgery and assisted suicide, it is the person upon whom the operation will be done (or his/her legitimate and informed guardian) who will make that decision. In the case of war and punishment (and possibly torture and other constraints on enemies), it is the state--the legitimate government of the public or the citizens in deliberative assembly.
Those who consider abortion as a medical procedure for birth control or for the good life of the mother usually do not support abortion because it is an act of violence, but recognize that the choice of necessity belongs to the woman who has been impregnated. They then act to achieve a public policy where abortion and indeed any invasive procedure is prevented through better education and healthy life styles. This includes universal health insurance as well as care of women
Those who want to make abortion a matter of public or state decision, rather than personal or private decision argue that they want to protect the life of another person--namely, the unborn child. And the fact that another person is present takes it from the private to the public sphere. And this is where the difference of opinion is cut. Is the fertilized egg or the fetus a human person? What makes an organism a human person?
Some say that whether or not you accept that the fertilized egg is a human person, it is on its way to becoming one and we have no right to interfere and stop the process. But that would argue to avoiding menstrual discharge or nocturnal or any seminal ejaculation since all eggs and sperm are oriented to procreation. Indeed, the ancient Hebrews who thought that the homunculus, the teeny person was contained in the male seed which was planted to grow in the female ground. Therefore that condemned the spilling of seed without implanting it. But that puts us on the road to absurdity.
In some religious traditions, a human person is constituted of matter from the earth and spirit from God. At the time of conception, the soul is "infused." So in the human sex act, as the sperm gets to the egg, is the act of God creating the soul. So any act to terminate the pregnancy after that infusion kills the human person and violates the act of God. St Thomas held that it was after three months that God infused the soul. Some said later. Anti-abortionists show ultrasound pictures of the fetus that has fingers and other characteristics of a human baby to be in order to prove that abortion is the killing of a voiceless human person.
And so the dispute is not between those who like and don't like abortion. It is between those who think that the state government should or should not prevent abortion based upon their definition of the human person. There are many who are sincere in thinking that the human person exists when God infuses the soul at conception and therefore government should protect the fetus. There are those who are sincere in their belief that the human person does not exist until the organism can communicate and interact with other human persons.
To be honest, I am of the latter persuasion. I do not approve of abortion, but I do not believe that the government should make the determination of whether or not a woman should have an abortion or whether any person should decide surgery or even assisted suicide. I also believe that the best way to prevent abortions, other invasive procedures, and violence against the person is by establishing the policies that will allow people to have the best information for them to decide.
I believe that ironically those who are most adamant about opposing abortion are the ones who are most encouraging its practice by denying health care and freedom of information to the general populace. Unfortunately those who would deny women the ability to choose abortion and who deny agencies like Planned Parenthood the ability to assist these women are the ones who make abortion desirable and even necessary. They have not been able to move beyond the realm of necessity to the realm of freedom and justice.