Daniel Dennette's philosophy speech examines Reductio ad Absurdum, a commonly used philosophical tool. In this speech, Dennette encourages philosophers to examine their methods more closely.
Reductio ad Absurdum is used to highlight an unrealistic premise with an absurd conclusion. Dennette uses the following example to explain this in his speech. When someone is running very late to dinner, but unrealistically claims that they'll be there on time one might say "he'll have to fly like Superman to get here for dinner." This is of course ridiculous because people can't fly and Superman is a fictional character, making this a good example of Reductio ad Absurdum.
As a philosopher Dennette believes philosophical methods deserve to be thoroughly examined and discussed. Dennette says that Reductio ad Absurdum is a key tool used in philosophical argumentation.