Rule 7 is that statements must use rigor. Rule 7a is that statements must have precision, accuracy and evidence. Rule 7b is that in order for an addition to an argument to be useful, it has to pass three tests. It has to be verifiable, meaningful, and relevant.

A verifiable statement is one that can be objectively demonstrated to be true or false. For example the statement, ‘It is going to rain tomorrow’ is verifiable, while this sentence in Boris Johnson and Michael Gove’s 2017 letter to Theresa May, ‘... in some parts of government the current preparations are not proceeding with anything like sufficient energy’ is not verifiable because it does not specify what parts of government, what ‘sufficient energy’ means, or how it is measured. That’s not to say the statement is false … or true. It’s just that there is no way to tell.

Second, statements need to be meaningful. In 2017, the White House responded to the US Global Change Research Programme’s statement on climate change by saying, ‘The climate has changed and is always changing.’ This statement is verifiably true. But it is meaningless because it says nothing about the degree, rate and cause of change, which are crucial elements in climate change.

When US Senate candidate Roy Moore was accused of sexual assault of a 14 year old, state auditor Jim Ziegler justified Moore’s behaviour by saying “Mary was a teenager and Joseph was an adult carpenter … [Moore’s behaviour was not] illegal or immoral. Maybe just a little unusual” To many people this may appear such a bizarre statement that it does not warrant analysis. But it does make sense to some people.

Given this disagreement, there is value in having a mutual method for analysing different opinions. The third step of this part of the method is to test for relevance; Ziegler does not give any explanation of how his (additionally unverifiable and meaningless) statement is relevant to an accusation of sexual assault. Is he, for example, saying that Mary/Joseph establishes a principle that can be applied generally? So according to him, are all contacts between adults and minors acceptable? Or if not, is he saying that there are specific exemptions that apply to both cases? In which case he would have to demonstrate what these are. In the absence of either preceding argument, his statement is irrelevant.

Rule 7b is a tool that is more subtle than raw disagreement. If disagreeing parties can accept the conditions of the debate, there is more chance to build agreement.