One of the best responses to any argument, of any kind, is simply to ask, “How do you know?”
That is, the most persuasive arguments answer in advance the “how do you know” question by setting out the pedigree of each proposition. This strategy of full disclosure is less advisable where your positions are weak. But when they are strong it can “shock and awe” your opponent into submission.
There is no more satisfactory feeling than to do your homework, lay out the arguments, and have your opponent concede that he cannot honestly hold back your tsunami of argument. Where your arguments are this good, it is often strategically advisable to lay them out in detail, even though doing so gives your opponent a chance to respond.
This is why lawyers love footnotes. A good footnote preempts argument by showing the support for the proposition. It allows the decision-maker to see how well supported the argument is. Legal argument even has a particular set of rules for citation that is intended to discipline and guide the use of references. These rules require a degree of disclosure of the kind of support provided by the material cited. It establishes a set of rules of the game regarding how we assert the pedigree of our knowledge.
However, preemptive display of the basis for your arguments provides an opportunity for your opponent to scrutinize those arguments for flaws. Thus, where your opponent sees that there is no footnote or other display of the pedigree of your information, or where the footnote shows weak support, he can seek to exploit your weakness. In reasoned argument, you always have a strategic choice whether to make preemptive display of your back up in citations or not, often depending on the context and the opportunity you will have to provide the support later.
On the other hand, where your opponent fails to set out the pedigree of his propositions, or where, after examining the pedigree of his propositions for yourself, you otherwise identify a weakness, you must put him to his proof. Following Highet’s strategy, you must pull on that loose thread and ask why we should believe this unsupported proposition. In a more nuanced way, you must test the quality of the pedigree of each of your opponent’s essential propositions—some may purport to be well supported, but may actually be weakly supported, or even contradicted. Facts can be appreciated in different ways, and support for a proposition is often in the eye of the beholder.
There are two types of knowledge that are important in law: knowledge of facts and knowledge of law. While lawyers may be adept at proving or disproving factual statements, the more characteristic part of legal practice involves determining what the law is. Importantly, there is an iterative, interdependent, relationship between law and facts.
The facts that we identify tell us what legal rules are likely to be applicable, and the legal rules tell us what facts are salient. For example, we do not know whether to examine the law of murder unless someone has died and we suspect improper causation: what is known in pre-modern detective stories as “foul play.” Once we see death and improper causation, we can look at the law of murder to see whether this is a case of murder.
The crime of murder has several factual elements that must be proven in order to convict the perpetrator. If one of the factual elements cannot be proven, another legal rule might apply. For example, if there was no bad intent on the part of the person who caused the death, we might examine the crime of manslaughter, or the civil wrong (“tort”) of wrongful death.
If there was bad intent, but no death, we might examine attempted murder or assault as possible crimes. Again, once we know some of the facts, we know where to look. Creative lawyers are those who are able to identify elements of crimes or causes of action that may not readily fit together or be perceived as a particular crime or cause of action.