Tag Archives: pro-choice

If-then statements and the abortion issue

6 Aug

“If you’re a man, you have no right to an opinion about abortion”


I read this statement in a letter to the editor the other day.  This assertion is useful for two reasons:

·         We can look at conditional if/then syllogisms that will support this assertion

·         AND we can practice teasing out the implications of this assertion by using something that sounds VERY sophisticated, but is actually quite simple – the “argumentum ad absurdum”

First, let’s consider a conditional argument:

If A, then B         If it is sunny today, then we will go on a picnic

A                           It’s sunny (we affirmed the 1st clause, the antecedent)

Tf, B                     Tf, we will go on a picnic (resulting in the 2nd clause, the  consequent)

The form of this hypothetical conditional syllogism is valid if we AFFIRM the “if-clause” (or the antecedent).  The other valid form that works is when we DENY the “then- clause” (called the consequent).

If it’s sunny today, (the antecedent) then we will go on a picnic (the consequent)

We didn’t go on a picnic (we denied the consequent)

Tf, it wasn’t sunny (resulting in a denial of the antecedent)


Now let’s look at the actual MEANING of the statement at the top.  The full argument looks like this:

           If you’re a man, then you have no right to an opinion about abortion

          You’re a man

          Tf, you have no right to an opinion about abortion


We affirmed the antecedent in Premise 2, resulting in a valid conclusion. What would the other valid form look like?

If you’re a man, then you have no right to an opinion about abortion

You have a right to an opinion about abortion

Tf, you must be a woman (you’re not a man)


We denied the consequent in Premise 2, resulting also in a valid conclusion.  But as we’ve seen before, just because an argument is VALID, the TRUTH of the premises is a separate issue.

This assertion in Premise 1 seems ridiculous at face value, but how do we approach it through reason?  We can show it to be false by applying the same ‘logic’ to other situations and seeing the results.

For example, would we apply the same reasoning to these circumstances?

  • ·         If you are not a concentration camp victim, then you have no right to an opinion about Nazis.
  • ·         If you are not a cancer patient, then you have no right to an opinion about meds.
  • ·         If you are not a teacher, then you have no right to an opinion about how children learn best.

Think about how government works – we elect men and women to represent us at the local, state and federal levels. We trust that they will be able to decide issues wisely AFTER studying the details. We don’t limit them to voting issues that they have ONLY personally experienced.   We don’t even hold our President, the Commander-in-Chief of the military to that standard.  Barack Obama has never served in the military, but we expect him to make informed decisions that impact the armed forces.

Where else do you see this smug assertion clobbering folks on both the left and the right? Remember how much easier it is to see others doing that to which we are blind in ourselves.  Humility heals.

Using the either/or to argue to a conclusion

5 Aug

“Either you are pro-choice or you are anti-women” 

We ran into this statement as an example of how we need to frame an attribute/predicate as either A or non-A to determine more easily if a pair of statements were truly contradictory.

Framing a contradiction into an either/or hypothetical proposition is one way to argue. We call this a Disjunctive Proposition.

Today we are FIRST going to form a valid or correct argument and then we’ll look at the truth of the major proposition.

Consider the ‘formula’ where P and Q are different statements, called ‘disjuncts’.  On the left is the model syllogism; in the middle and on the right are two samples.

Either P or Q                   Either blue or red            Either she had a boy or a girl

Not  P                               Not blue                             She didn’t have a boy

Therefore, Q                   Tf, red                                 Tf, she had a girl

These arguments work; that is they are valid BECAUSE the major proposition that contains the disjunctive statement tells us that one of the 2 disjuncts is true. (we have to accept this as a given;  we’re NOT going to argue about the truth of that major premise YET.)   So if one disjunct (P or Q) is NOT true, then the other HAS to be true.

What happens, though, if in the 2nd premise, I AFFIRM one of the disjuncts? Can this kind of syllogism work the other way?  It would look like this:

           Either Susie travels to the UK or to France

          Susie travels to France (I’m AFFIRMING one of the 2 disjuncts)

          TF, she does not travel to the UK

No….this set up is INVALID for I have actually assumed MORE than the information given.  It could very well be that her journey takes her to BOTH France and the UK.  All we know from the major premise is that she AT LEAST travels to one of the 2 places.  It does NOT claim that if Susie travels to one, she does NOT then travel to the other.

Certainty exists ONLY if the minor premise (the proposition that denies or affirms one of the disjuncts) denies one of the disjuncts since we have as a given that ONE has to be so.

Either I had a salad for lunch or some soup.

I did not have soup

Tf, I had salad

Back to our original Disjunctive propositions:  Either you are pro-choice or you are anti-women.  Once we have determined that the syllogism is set up correctly, that it is valid, THEN we look at the truth of the major premise.

If you remember what we looked at last Friday, we talked about true dilemmas and the Fallacy of the False Dilemma.  So, is our disjunctive proposition a False Dilemma?

If you are willing, comment with your thoughts about how you would determine the truth or falsity of that proposition.  A lot is riding on your answer!

“That’s a contradiction!” – are you sure?

30 Jul

So…how does knowing the Law of Non-Contradiction help in real life?

Remember we said that according to this DISCOVERED law (it’s built into the fabric of our universe by God as opposed to invented by culture):

 A & non-A cannot both exist at the same time and in the same way.

Consider this pair of statements:

  • ·         Susie is pregnant
  • ·         Susie is not pregnant 

Now we have to be careful and not automatically ASSUME that this is a contradiction. Two propositions that LOOK contradictory could in fact be explained…….

1.    If we mean that Susie Jones is pregnant, but Susie Smith is NOT pregnant (2 different Susies)

2.    Or if we mean that Susie is pregnant with many good ideas, but Susie is NOT pregnant with child (pregnant as an analogous term – referring to different but related concepts)  

But if we are talking about the one and only Susie Smith and we understand the predicate term ‘pregnant’ to indicate about to have a baby, then….

·         They cannot both be true OR false at the same time and in the same sense.

In Christianity this law of logic helps me sort out my theology.

My favorite attribute of God is His sovereignty.  When we say that God is sovereign, we understand God to be 100 % in charge of all that happens, the good and the bad.  I’m not saying that I understand this characteristic of God, but I am comforted by it!  (If God allows suffering and evil, then He must have a good purpose for it even if I can’t see that…yet!)

Therefore, because of the Law of Non-Contradiction, when I assert that God is always sovereign I cannot say:

God is sovereign


God had no control over that deadly train accident in Spain.     

That would be saying:  God is sovereign over all/ God is NOT sovereign over all

Either God IS sovereign or He is not, if I take sovereign to mean that He controls all molecules in the universe.

What we have to do when hit with confusing statements that seem irreconcilable is to ‘translate’ them, if possible, into A and non-A forms.  Then we can evaluate them clearly.

I say, ‘if possible’ with this caveat in mind – you might run across an either/or claim –

·         God is either all-loving or He is a God of wrath.

·         You’re either pro-choice or you are anti-women.   

If you can’t ‘translate’ the 2 predicates into an A and a non-A term, then you might be facing the Fallacy of Bifurcation (aka ‘false dilemmas’).  We’ll talk about that on our next Fallacy Friday!

Back to the above assertions – If we wanted to deal with that first claim, we’d have to re-frame it and then discuss terms.

·         God is either all-loving or He is not all-loving

·         You’re either pro-women or not pro-women

 Your HW for the next few days is to keep an ear out for ‘either/or’ claims and try to determine if they are in fact contradictory or perhaps examples of the False Dilemma fallacy or actually TRUE!