Thursday, 27 March 2008

Why substituting words does not turn the tables on an argument.

Find believes that by substituting words in my stated belief below that she has "turned the table on my argument". The intent of this post is to show why I think she is mistaken.

(Find, I'm not sure whether you're a he or a she, I chose She, my apologies if I am wrong about that.)

Here is the refresher, for those of you who have forgotten, or who were not following the comments on that particular post:

Me - "I believe that whether or not to continue a pregnancy should be between a woman, her medical practitioner, and her own God. The law has no business meddling in private reproductive decisions."

Find - "Slight rewording:
'I believe that whether or not to rape should be between a man, his medical practitioner, and his own God. The law has no business meddling in private reproductive decisions.'
Please don't spout such illogical drivel when it it is so easy to turn the tables on it."

Me - That kind of retort is what we call an Appeal to Emotion.

Find - "Actually, no, all I did was substitute a few words using your logic. If my statement is an appeal to emotion, then, logically, so was yours!"

Ummm, actually, no. That only works if your substitution retains the truth of the premises.

We'll try it on a classic argument:

P1 Socrates is a man
P2 All men are mortal
C Socrates is mortal

Now, let us try some substitution, how about, "ape" for "man"?

P1 Socrates is an ape
P2 All apes are mortal
C Socrates is mortal

In this case, the argument is still valid (if the premises are true, the conclusion must be true) but it is now unsound because P1 is false. Socrates was not an ape.

... and one more example, how about "unable to bear children" for "mortal"?

P1 Socrates is a man
P2 All men are unable to bear children
C Socrates cannot bear children

In this case the argument retains its soundness as it is true that men cannot bear children.

If my statement, were an argument, which it clearly was not. (It laid out my preference for the way abortion ought to be handled. Premises leading to a conclusion were nowhere in sight.) Changing the gender to male, and the action to rape within the context of a reproductive decision was, as far as I can tell (and I have three years of university level logic) doomed to failure. Abortion and rape have less in common than Socrates and his ape cousins.

However, I may have a formal logic eduction, but I do not have your drive, Find, so perhaps you can come up with a valid argument against abortion which does not have its soundness compromised by those substitutions? Should be an interesting exercise if nothing else.

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