The Failed Logic of the So-Called Pro-Life Movement

I have been thinking for some time about the poor logic used by the Christian Right in the so-called pro-life movement.  I say "so-called" because I do not think for a minute this movement is really pro-life.  Their singling out of abortion as the only issue they focus on is one reason why.  I know someone from my own Catholic parish who said that they will turn to the other "life" issues, guns, a living wage, universal healthcare, a sustainable environment, clean air and water, and capital punishment and war, after the repeal of Roe v. Wade. Yet, here we are, a full year after Roe is struck down, and this movement is still fixated on this one issue.

I have a good friend who was at one time one of the main movers and shakers in the movement, who has now moved to a pro-choice position, not because he is in favor of abortion itself (as indeed I am not), but because he could no longer live with the political hypocrisy of the movement.  He says he was in the room when pro-lifers and Republican politicians cut deals.  "You back our tax cuts and we will give you your pro-life judges."  I always thought something morally fishy was at play in the movement, and so, even as a Christian pacifist, I have denounced it.

But I want to take this opportunity not to talk about the political hypocrisy of those who call themselves pro-life, although I believe there is ample hypocrisy to be found there.  I think the whole movement is disingenuous, deceptive, and manipulative,  Because I believe in the sanctity of life, I have denounced the pro-life movement.  This movement, and the conservative Christians comprise it, are, at best, in my view, SELECTIVELY PRO-LIFE. It is something I wish to have nothing to do with.  As foul and offensive as abortion is, I believe forced birth is even more so.

But this evening I want to write about a logical problem the movement has, a problem which has become clear to me in the past week or so, but not one I have seen anyone put into words.  In short, any form of an anti-abortion argument which says we know when  life begins is based on a serious logical flaw. My own son, who is a medical doctor, when I shared this idea with him, said this is why he is a scientist and I am a philosopher.  I have used the hypothetical I am going to put before you in this piece dozens of times in the classroom, but the full impact of it has not hit me until recently.

It is a fundamental principle of logic that no conclusion can ever be drawn from a single premise.  In fact, any argument based on just one premise must be rejected.  The reason is an argument which is based on one premise only is not deductively valid.

Valid is a term which many people throw around even though they have no clue what it means. Saying something is valid is not like saying it is a legitimate point of view.  Saying something is valid is not like saying someone makes a good point.  Valid is a technical term.  If an argument is valid, it means the form of the argument is such that it is impossible for the conclusion to be false if the premises are true.

The way I explain this to students is that good logic has to have two things going for it.  It has to have correct factual assertions, and they have to be in the correct form.  When the form is correct, the argument is called valid, and if the information is correct, and  in valid form, the argument is called sound.  The main pro-life arguments that abortion is the taking of  a human life are neither valid nor sound.

PLEASE DO NOT MISTAKE ME HERE.  I am not saying abortion is good.  I am not saying abortion is something we should broadly advocate for.  It may well be that abortion is always morally wrong.  I AM JUST SAYING THE PRO-LIFE MOVEMENT FAILS TO MAKE THAT CASE, no matter what definition one chooses for the beginning of life.

I put this hypothetical to my students.  Say you are outside an abortion clinic and someone yells out, "ABORTION KILLS A HUMAN BEING, THEREFORE ABORTION IS WRONG."  That may be true, but put this way there is no obligation to accept this position, because, as I said above, this is an attempt to draw a conclusion from only one premise.   This argument is invalid.

Much of the time, an invalid argument can be fixed, made valid, by supplying the missing premise.  Nearly always, the missing premise can be supplied by an "if...then..." statement.  For example:

Premise 1: Abortion is an act that kills a human being.

Premise 2:  If abortion is an act that kills a human being, abortion is morally wrong.

Conclusion:  Therefore, abortion is morally wrong.

Now we have an argument which is logically valid.  Whether it is sound will depend on whether one can show that both premises are true. 

In an argument like this one that leads to three possibilities.  Perhaps none of the premises are true, or perhaps only one is true, in which case the argument is valid but not sound.  Perhaps both premises are true in which case the argument is BOTH valid and sound.  Or we may not be able to demonstrate one or more premises are true or false, in which case we still know the argument is valid, but we do not know if it is sound.  I am suggesting pro-life arguments are in this third category, as I will explain below.

Recently a dear friend shared with me that abortion is murder because from  the moment of conception there is unique DNA.  I would suggest this is shoddy reasoning which no one should find persuasive.  I am not saying my friend is wrong to say abortion is murder, I am saying my friend is trying to draw a conclusion from only one premise.  This friend's argument goes like this:

From the moment of conception there is unique human DNA, therefore abortion is murder.

To illustrate what I am getting at, I am going to "fix" the argument in the same way I did above.

Premise 1:  From the moment of conception, there is unique human DNA.

Premise 2: If, from the moment of conception, there is unique human DNA, then abortion is murder.

Conclusion:  Therefore, abortion is murder.

Now, we have an argument which we can at least intellectually work with.  We have an argument in valid form.  This allows us to move on in the process to see if the premises are indeed true.

In this instance, I think Premise 1 is impossible to deny.  We do know that there is unique DNA from the moment of conception.

The problem is Premise 2.  I need another argument to show me that the presence of the DNA from Premise 1 means life has begun.  I do not think anyone can demonstrate that, all they can do is stipulate it.  Saying it is so does not make it so, and philosophically we need far more than what is here to make the case.

And the interesting thing is, if I drop the DNA argument and substitute some other proposed definition of the meaning of when life begins, I have the same problem.  If I substitute a heartbeat, or viability, or the ability to feel pain, I have the same problem.

I am not saying none of these definitions of when life starts is true.  I am saying you cannot expect someone to just accept them as true. It is necessary to demonstrate they are true instead of just stipulate or assert they are true. The bottom line then is, I think it is philosophical hubris to say we know when life begins, and it is philosophical humility to admit we do not know.