Skip to content

Faulty Logic

Dec 12, 2008
tags:

I’m sorry, I can’t help myself. Although I apologize for not writing about this sooner. I read this article from the Dec 5 issue of the Philippine Daily Inquirer, and the mathematician in me cannot let this pass.

This statement caught my eye:

Indeed, you don’t need to be a doctor to know that if p implies q, then not p implies not q.

Uh-oh. Wrong. Everyone who studied logic would immediately say that this is a faulty statement. Take for example, we consider this statement:

If I won the lottery, I would be rich.

In this case, statement p would be “If I won the lottery,” while statement q is “I would be rich.”

Now consider this. Suppose that I didn’t win the lottery. Would it follow that I cannot get rich? Of course not! There are other ways for me to get rich (say if I married someone who won the lottery) aside from winning the lottery. So it doesn’t follow that I will not be rich. This is a simple illustration of the fact that if p then q, it doesn’t follow that if not p, then not q.

But if we read the article carefully, maybe there was a typographical error. Maybe he meant that if not q, then not p. This is the contrapositive of the statement if p, then q. Let us now analyze the article itself.

If we need more proof that professional stupidity is an occupational hazard of the office of a political spokesman, consider Deputy Presidential Spokesperson Anthony Golez’s defense of his provocative remarks about political immaturity. Asked whether he thought the debilitating street protests in Bangkok would happen in Manila too, he had said no, “because our people have reached a high degree of political maturity whereby our people respect due process and the rule of law.”

Breaking this down, then statement p would be:

Our people have reached a high degree of political maturity whereby our people respect due process and the rule of law.

Statement q is:

The debilitating street protests in Bangkok would not happen in Manila.

If p, then q. If not q, then not p. We know for a fact that there were street protests in Bangkok. Hence the writer’s conclusion in his article.

In other words, Thais, according to Golez, were politically immature. He did not say it outright; he did not need to. That’s basic logic, something a medical doctor of Golez’s quality and administrative ability would have easily followed.

This is an obvious conclusion based on simple logic. Amazing.

Lesson learned from this logic exercise: Be careful with your statements. It’s hard to be a political spokesman, don’t you think?

Advertisements
No comments yet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: