Are All “Critical Questions” For Argument Schemes Critical?
Comments: 1 - Date: May 13th, 2007 - Categories: Uncategorized
Professor Tillers notes that “witness credibility is perhaps the most complex inference problem known to ordinary mortals.” http://tillerstillers.blogspot.com/2007/05/joseph-laronge-demonstrates-how-to-use.html. That has been my experience in litigation. The concept of “critical questions” is very helpful in addressing this problem (e.g. is the witness biased?; does the witness have the necessary sensory abilities?)
Critical questions have been modeled as “assumptions” and “exceptions” depending on “allocating the burden of production to the party with better access to the evidence.” http://io.uwinnipeg.ca/~walton/papers%20in%20pdf/07%20GordonPrakkenWalton%20CarneadesPreprint.pdf. Critical questions have also been distinguished based on the role they play. http://www.ai.rug.nl/~verheij/publications/pdf/ai&l2003.pdf.
For legal arguments, I suggest a simple pragmatic criteria for distinguishing critical questions: 1) those that are “conditionals” upon which the inference from the testimony is contingent; and, 2) those that are “companions” that modulate the strength of the inference from the testimony but are not “critical.” For example, whether the event was in the observer’s perceptual range is a condition for any degree of inference. To the contrary, whether the witness is biased is a companion to the inference that only effects its degree of strength. In attempting to persuade the fact finder, this distinction is the one that is “critical.”
The following argument maps illustrate these two types of “critical questions” portrayed as premises outside the direct inferential path. The first map uses the Pyramid visual language. The second map uses the Path visual language by removing the redundancies required in the Pyramid visual language and by restructuring the inferences based on the Path template for increased readability. When the six redundant premises are removed from the Pyramid map, the inference steps are revealed as simple linear steps. And the “critical questions” cannot be confused with co-premises since they do not share the same visual syntax as required in a Pyramid map. 
