Truth claims are stronger if there is a contradiction

It is more difficult in dialogue to establish a positive claim than to contradict or refute claims made by others. A way in which we can make truth claims more substantive is to align them with contradictions. We might say if a is not equal to b then c. This places the emphasis on conflating the equivalence of a and b rather than simply contradicting c.

For example two truth claims which are difficult to establish in political dialogue are the advantages of a proportional voting system and the disadvantages of fractional reserve banking.

Rather than simply to assert our preferences this style of rhetoric makes it easier to make a convincing argument. Proportional representation is good because otherwise politicians will ignore the electorate. The second half of the sentence strengthens the claim made in the first half of the sentence. We have placed a (contradictory) condition on our being convinced that pr is not good. If someone can show that politicians listen to the electorate despite the absence of pr then we will be convinced. Because this second condition is a contradiction we are now free to reject all other arguments... to the person in dialogue with us we will never be convinced because they are trying to show an equivalence between things we have seen to be different. They will find it a very difficult task to show that politicians are responsive to the electorate under the existing system.

Another example of this kind is fractional reserve banking. An example of this type of conjunctive rhetoric would be to say that the economy is bad because of fractional reserve banking. Then the burden rests with the person we are talking to to show that the economy is not bad which is more difficult.