Nov 11, 2020

Don't Play with the Meaning of Words

2 Min Read

When we’re talking about the truth of God, it’s important that everyone is agreed on what we mean by the words we use. In this brief clip, R.C. Sproul reveals what happens when we try to change the meaning of our words in the middle of a conversation.


Equivocal language is language where the meaning of the term changes dramatically in the course of the conversation. I illustrate this when I teach logic to my seminary students and teach them the fallacy of equivocation. And I show them the fallacy of equivocation by proving that cats have nine tails. Remember the time I proved to you, Roger, that cats have nine tails? We’re going to do it again.

My first premise in my syllogism is this: no cat has eight tails. Do you agree with that, Roger? You’ve never seen a cat with eight tails, have you? Okay, well I’m going to prove to you that cats have nine tails. No cat has eight tails, right? Now here’s my question: If I have two boxes up here and one box has a cat in it, and the other box is empty—you’ve got an empty box here and a box with a cat in it here. Now, I’m going to test your knowledge of arithmetic and mathematics. How many more cats are in this box, Roger, than are in this box? One. Thank you very much. How many more cats’ tails are in this box than in this box? One. And how many cats are in this box? Zero. I’ve got no cat in this box and one cat in this box, right? So, I have one more tail in this box than I have in this box.

So, I say here, one cat has one more tail than no cat. Now this is just a simple matter of deduction. If no cat has eight tails and one cat has one more tail than no cat, then how many tails does one cat have? QED, right? Eight and one makes what? Nine. So, one cat, then—the conclusion by resistless logic is that one cat has nine tails. Now, I tricked you, and what was the trick? What happened in this line of reasoning? The meaning of this term “no cat” changes in the middle of the discussion. It means something completely different here than it means here, and that’s called the fallacy of equivocation.