Which logical fallacy is used in the text?
Johnny must not have enjoyed the casserole, or he would have asked for a second serving.

 - false dichotomy: an argument that presents only two choices when more options exist
 - circular reasoning: an argument that supports a claim with the claim itself
 - ad hominem: an attack against the person making the argument, rather than the argument itself
The text argues that if Johnny enjoyed the casserole, then he would have eaten more. However, Johnny could have enjoyed the casserole without wanting a second serving. This illustrates a type of logical fallacy known as a false dichotomy.