Clarence Darrow and William Jenning Bryant

What is a reductio ad absurdum cross-examination? It is the process of refuting a claim on the grounds that it is absurd. If the proposition is accepted then there will be a patently untenable result. 

In the past few posts, we have been focusing upon the first impeachment wrecking crew—Unreliability of the Witness’s Observation  (Impeaching a Biased Witness and Cross-Examining a Child). Now, we move on to the second impeachment wrecking crew—The Faulty Report. The concept here is that the report given by the witness is improbable because it is absurd. 
Cross-examination to show the witness’s account is improbable is supported by Evidence Rule 401. Test for Relevant evidence, which states, “Evidence is relevant if:
(a) it has any tendency to make the existence of any fact more or less probable than it would be without the evidence; and

(b) the fact is of consequence in determining the action. 
All relevant evidence is admissible, except . . .” 
There are three techniques you can employ to show the report is improbable:
1. Reduction to the Absurd Technique
2. Common Sense Technique
3. Contradictory Conduct Technique
The 1925 Scopes trial provides an excellent illustration of the Reduction to the Absurd Technique. Here is a brief summary of the facts of the case and the lawyers involved.
  The trial took place in Dayton, Tennessee
  John Scopes was accused of teaching evolution in violation of state statute
 William Jennings Bryan – former candidate for President and head of the fundamentalist   movement becomes co-counsel for the prosecution
  Clarence Darrow signs on as co-counsel for defense
The trial drew such a crowd that they thought the courtroom floor would collapse and they moved the players outside as pictured below.

A book “Inherit the Wind” was written about the trial and it was later made into a movie by the same name. The cross-examination in the movie is based on the trial transcript.
Watch as Darrow cross-examines Bryan.

The jury deliberated 9 minutes and found Scopes guilty. The court levied an hundred dollar fine on Scopes.  Bryan died five days later.