INFERENCE PATH

What is the glue that links premises to their conclusion? I have been suggesting in this blog that the transitivity of predication (essential) is one glue that can bind any argument…at least for practical purposes in litigation. I didn’t know until I read an article this week that, therefore, I am a hedgehog.

Leo Groarke wrote an intriguing article on logic using the Greek parable of the Fox and the Hedgehog. In a review of the article, Preyer and Mans state that “[t]he fox uses 36 tricks to escape his enemies, the hedgehog has only one, but this one and only trick works perfectly. The fox symbolizes of course the type of argumentation theory, which uses many type of glues while the hedgehog has only logic to tie premises and conclusion together.”

Dr. Leo Groarke states that deduction is a glue that can bind any argument. My sole bottle of reasoning glue is, instead, filled with the transitivity of predication. And, further, I suggest that it is the optimum glue for litigation.

Dr. John Woods is, apparently, a fox who disagrees. After just posting a discussion on the importance of using a reasoning mode of “logical necessity” in litigation, I ironically read a wonderful article by Dr. John Woods, “Eight Theses Reflecting on Stephen Toulmin.” Dr Woods’ Thesis One is that “[t]he validity standard is nearly always the wrong standard for real-life reasoning.” In the domain of litigation, I respectfully disagree. (Admittedly, I did not fully comprehend all of his reasoning in the article. This fact is not a reflection of its coherence, but rather my own limitations. Even so, the article was enlightening for me.)

Consider the following argument map.

In civil litigation, the goal is to design a bridge of stepping stones that is perceived as more “sound” (e.g., less uncertain, less risky, safer to traverse, or more stable) than one’s opponent’s, that infallibly leads to one’s main contention on the other side of the bridge. In criminal litigation, the goal for the prosecution is to design such a bridge that the jury believes that they can cross beyond a reasonable doubt.

In my opinion, building a bridge in which the stepping stones may be 100% stable and certain but which may not lead to the main contention (e.g., questions raised on validity or logical necessity) is much less useful in litigation. Validity is, admittedly, not the goal, but it is one of the standards, in my opinion, of a compelling bridge design in litigation.

Dr. Woods argues that proof based on validity is a “brittle” accomplishment since “a single disruption of the reasoner’s knowledge-set” can render the argument “impotent.” He states that “[v]alidity is wholely indifferent to new information.” But the attorney is not indifferent.

When new contradictory information to a stepping stone arrives on the scene, the attorney has at least two options. If the new contradictory information is irrefutable, the attorney redesigns the bridge to accommodate the change in factual topography, but the destination, even with some qualification, can still win the case (unless ethically it becomes apparent that the journey should be abandoned) and the bridge should still connect to that destination with logical necessity. This redesign is typically done by adding qualifiers that increase the precision of the bridge to accommodate the new information. And an increase in precision should lead to a reduction in the perception of uncertainty.

Or in the alternative, the attorney may argue that while the new information may increase the uncertainty of reaching the destination, the reduced level of certainty is still sufficient for the attorney’s client to win.

Consider the two argument maps below using an example drawn from Dr. Woods’. The first map metaphorically illustrates induction. In this case, assuming the premise is accepted, the uncertainty of the argument resides with the unknowns attached to the inference leap. Is it too big a leap for the juror to make? Is a leap to another destination more plausible? Even if the premise seems 100% certain, the juror observes the uncertainty in the inference. There is no logical necessity.

This next argument map depicts the same circumstance using the transitivity of predication as the glue. Here the uncertainty, assuming the first premise is accepted, rests on the stability of the second premise. But the stepping from one stepping stone to the next is easy for the juror. The inference has no uncertainty.

Given that the circumstances are the same, the amount of uncertainty, theoretically, should be the same in both maps. In litigation, in my experience, it doesn’t work that way. Here is, in my opinion, why.

Dr. Woods argues that logic must take into account cognitive orientation. In litigation, this includes the “computational capacity” of the juror as “individual agent.” The individual juror, or even the judge, like other typical adults, have a functional understanding of transitivity according to research. The same cannot necessarily be said for a functional understanding of abduction, every type of presumption inference, and other modes of reasoning. Without this same level of functional familiarity, there is an increase in uncertainty that the juror will not reach the main contention destination because there is additional uncertainty that resides in the computational capacity of the individual agent for non-transivity reasoning bridges.

And if reasoning is bounded by the neurology and consciousness of the individual agent, from a kinesthetic neurology sense, my guess is that people in general are more willing to step onto shaky ground than to make a leap into space.

Further, from a practial reasoning perspective, as depicted in the Toulmin derived argument map example of “Harry is a British subject.” above, every stepping stone relies on assumptions (e.g., the answers to “critical questions”) that support them. While every generalization may not have the single counter-example characteristic, (http://io.uwinnipeg.ca/~walton/papers%20in%20pdf/02modus.pdf), every generalization can be defeated, from a practical perspective, by eliminating a single underlying supporting assumption. From a practical litigation perspective, a transitive predication inference path with ubiqutous underlying supporting assumptions is still a reasoning mode of logical necessity.